diff --git a/data/Smarty/templates/default/mail_templates/order_mail.tpl b/data/Smarty/templates/default/mail_templates/order_mail.tpl
index b58cd99a86..5d9d58ae6e 100644
--- a/data/Smarty/templates/default/mail_templates/order_mail.tpl
+++ b/data/Smarty/templates/default/mail_templates/order_mail.tpl
@@ -56,7 +56,7 @@
 
 <!--{/section}-->
 -------------------------------------------------
-小　計 ￥<!--{$arrOrder.subtotal|n2s|default:0}--> <!--{if 0 < $arrOrder.tax}-->(うち消費税 ￥<!--{$arrOrder.tax|n2s|default:0}-->)<!--{/if}-->
+小　計 ￥<!--{$arrOrder.subtotal|n2s|default:0}-->
 
 <!--{if $arrOrder.use_point > 0}-->
 値引き ￥<!--{$arrOrder.use_point*$smarty.const.POINT_VALUE+$arrOrder.discount|n2s|default:0}-->
diff --git a/data/Smarty/templates/mobile/mail_templates/order_mail.tpl b/data/Smarty/templates/mobile/mail_templates/order_mail.tpl
index 84de76be3d..ef2806f60a 100644
--- a/data/Smarty/templates/mobile/mail_templates/order_mail.tpl
+++ b/data/Smarty/templates/mobile/mail_templates/order_mail.tpl
@@ -49,7 +49,7 @@
 
 <!--{/section}-->
 
-小　計 ￥<!--{$arrOrder.subtotal|n2s|default:0}--> <!--{if 0 < $arrOrder.tax}-->(うち消費税 ￥<!--{$arrOrder.tax|n2s|default:0}-->)<!--{/if}-->
+小　計 ￥<!--{$arrOrder.subtotal|n2s|default:0}-->
 
 <!--{if $arrOrder.use_point > 0}-->
 値引き ￥<!--{$arrOrder.use_point*$smarty.const.POINT_VALUE+$arrOrder.discount|n2s|default:0}-->
diff --git a/data/class/SC_Fpdf.php b/data/class/SC_Fpdf.php
index 9a2b57af16..fb7995fc13 100644
--- a/data/class/SC_Fpdf.php
+++ b/data/class/SC_Fpdf.php
@@ -155,6 +155,11 @@ private function setShopData()
         //ロゴ画像
         $logo_file = PDF_TEMPLATE_REALDIR . 'logo.png';
         $this->Image($logo_file, 124, 46, 40);
+
+        if (defined('INVOICE_REGISTRATION_NUM')) {
+            $text = '登録番号: '.INVOICE_REGISTRATION_NUM;
+            $this->lfText(125, 87, $text, 8);
+        }
     }
 
     private function setMessageData()
@@ -228,6 +233,8 @@ private function setOrderData()
         $monetary_unit = '円';
         $point_unit = 'Pt';
 
+        $arrTaxableTotal = [];
+        $defaultTaxRule = SC_Helper_TaxRule_Ex::getTaxRule();
         // 購入商品情報
         for ($i = 0; $i < count($this->arrDisp['quantity']); $i++) {
             // 購入数量
@@ -249,9 +256,18 @@ private function setOrderData()
                     $arrOrder[$i][0] .= ' * '.$this->arrDisp['classcategory_name2'][$i].' ]';
                 }
             }
+
+            // 標準税率より低い税率は軽減税率として※を付与
+            if ($this->arrDisp['tax_rate'][$i] < $defaultTaxRule['tax_rate']) {
+                $arrOrder[$i][0] .= ' ※';
+            }
             $arrOrder[$i][1]  = number_format($data[0]);
             $arrOrder[$i][2]  = number_format($data[1]).$monetary_unit;
             $arrOrder[$i][3]  = number_format($data[2]).$monetary_unit;
+            if (array_key_exists($this->arrDisp['tax_rate'][$i], $arrTaxableTotal) === false) {
+                $arrTaxableTotal[$this->arrDisp['tax_rate'][$i]] = 0;
+            }
+            $arrTaxableTotal[$this->arrDisp['tax_rate'][$i]] += $data[2];
         }
 
         $arrOrder[$i][0] = '';
@@ -270,18 +286,21 @@ private function setOrderData()
         $arrOrder[$i][1] = '';
         $arrOrder[$i][2] = '送料';
         $arrOrder[$i][3] = number_format($this->arrDisp['deliv_fee']).$monetary_unit;
+        $arrTaxableTotal[intval($defaultTaxRule['tax_rate'])] += $this->arrDisp['deliv_fee'];
 
         $i++;
         $arrOrder[$i][0] = '';
         $arrOrder[$i][1] = '';
         $arrOrder[$i][2] = '手数料';
         $arrOrder[$i][3] = number_format($this->arrDisp['charge']).$monetary_unit;
+        $arrTaxableTotal[intval($defaultTaxRule['tax_rate'])] += $this->arrDisp['charge'];
 
         $i++;
         $arrOrder[$i][0] = '';
         $arrOrder[$i][1] = '';
         $arrOrder[$i][2] = '値引き';
-        $arrOrder[$i][3] = '- '.number_format(($this->arrDisp['use_point'] * POINT_VALUE) + $this->arrDisp['discount']).$monetary_unit;
+        $discount_total = ($this->arrDisp['use_point'] * POINT_VALUE) + $this->arrDisp['discount'];
+        $arrOrder[$i][3] = '- '.number_format($discount_total).$monetary_unit;
 
         $i++;
         $arrOrder[$i][0] = '';
@@ -311,6 +330,22 @@ private function setOrderData()
         }
 
         $this->FancyTable($this->label_cell, $arrOrder, $this->width_cell);
+
+        $this->SetLineWidth(.3);
+        $this->SetFont('SJIS', '', 6);
+
+        $this->Cell(0, 0, '', 0, 1, 'C', 0, '');
+        // 行頭近くの場合、表示崩れがあるためもう一個字下げする
+        if (270 <= $this->GetY()) {
+            $this->Cell(0, 0, '', 0, 1, 'C', 0, '');
+        }
+        $width = array_reduce($this->width_cell, function ($n, $w) {
+            return $n + $w;
+        });
+        $this->SetX(20);
+
+        $message = SC_Helper_TaxRule_Ex::getTaxDetail($arrTaxableTotal, $discount_total);
+        $this->MultiCell($width, 4, $message, 0, 'R', '');
     }
 
     /**
diff --git a/data/class/helper/SC_Helper_TaxRule.php b/data/class/helper/SC_Helper_TaxRule.php
index d01b50b54f..b0b5324097 100644
--- a/data/class/helper/SC_Helper_TaxRule.php
+++ b/data/class/helper/SC_Helper_TaxRule.php
@@ -62,6 +62,85 @@ public static function sfTax($price, $product_id = 0, $product_class_id = 0, $pr
         return SC_Helper_TaxRule_Ex::calcTax($price, $arrTaxRule['tax_rate'], $arrTaxRule['tax_rule'], $arrTaxRule['tax_adjust']);
     }
 
+    /**
+     * 消費税の内訳を返す.
+     *
+     * 税率ごとに以下のような連想配列を返す.
+     * - discount: 税率毎の値引額
+     * - total: 値引後の税込み合計金額
+     * - tax: 値引後の税額
+     * 値引額合計は税率ごとに按分する.
+     * 課税規則は標準税率の設定を使用する.
+     *
+     * @param array{8?:int, 10?:int} $arrTaxableTotal 税率ごとのお支払い合計金額
+     * @param int $discount_total 値引額合計
+     * @return array{8?:array{discount;int,total:int,tax:int}, 10?:array{discount;int,total:int,tax:int}}
+     */
+    public static function getTaxPerTaxRate($arrTaxableTotal, $discount_total = 0)
+    {
+        $arrDefaultTaxRule = static::getTaxRule();
+
+        ksort($arrTaxableTotal);
+        $cf_discount = 0;
+        $taxable_total = array_sum($arrTaxableTotal);
+        $divide = [];
+        $result = [];
+
+        // 按分後の値引額の合計（8%対象商品の按分後の値引額 ＋ 10%対象商品の按分後の値引額）が実際の値引額より＋－1円となる事への対処
+        // ①按分した値引き額を四捨五入で丸める
+        foreach ($arrTaxableTotal as $rate => $total) {
+            $discount[$rate] = $taxable_total !== 0 ? round(($discount_total * $total / $taxable_total), 0) : 0;
+            $divide[$rate] = [
+                'discount' => intval($discount[$rate]),
+            ];
+            $cf_discount += $divide[$rate]['discount'];
+        }
+        // ②四捨五入したとしても、四捨五入前の値引額がそれぞれ 16.5 + 75.5 の場合 →(四捨五入端数処理)→ 17 + 76 両方繰り上がる。事への対処
+        $defaultTaxRule = $arrDefaultTaxRule['calc_rule'];
+        $diff = $discount_total - $cf_discount;
+        if ($diff > 0) {
+            $divide[$defaultTaxRule]['discount'] += $diff;
+        } elseif ($diff < 0) {
+            $divide[$defaultTaxRule]['discount'] -= $diff;
+        }
+
+        foreach ($arrTaxableTotal as $rate => $total) {
+            if ($rate == $defaultTaxRule) {
+                $discount[$rate] = $divide[$defaultTaxRule]['discount'];
+            } else {
+                $discount[$rate] = $taxable_total !== 0 ? round(($discount_total * $total / $taxable_total), 0) : 0;
+            }
+            $reduced_total = $total - $discount[$rate];
+            $tax = $reduced_total * ($rate / (100 + $rate));
+            $result[$rate] = [
+                'discount' => intval($discount[$rate]),
+                'total' => intval($reduced_total),
+                'tax' => intval(static::roundByCalcRule($tax, $defaultTaxRule)),
+            ];
+        }
+        return $result;
+    }
+
+    /**
+     * 消費税の内訳の文字列を返す.
+     *
+     * 複数の税率がある場合は改行で区切る.
+     *
+     * @param array{8?:int, 10?:int} $arrTaxableTotal 税率ごとのお支払い合計金額
+     * @param int $discount_total 値引額合計
+     * @return string (<税率>%対象: <値引後税込合計>円 内消費税: <値引後税額>円)
+     */
+    public static function getTaxDetail($arrTaxableTotal, $discount_total = 0)
+    {
+        $arrTaxPerTaxRate = static::getTaxPerTaxRate($arrTaxableTotal, $discount_total);
+        $result = '';
+        foreach ($arrTaxPerTaxRate as $rate => $item) {
+            $result .= '('.$rate .'%対象: '. number_format($item['total']).'円 内消費税: '.number_format($item['tax']).'円)'.PHP_EOL;
+        }
+
+        return $result;
+    }
+
     /**
      * 設定情報IDに基づいて税金付与した金額を返す
      * (受注データのようにルールが決まっている場合用)
diff --git a/tests/class/helper/SC_Helper_TaxRule/SC_Helper_TaxRule_TestBase.php b/tests/class/helper/SC_Helper_TaxRule/SC_Helper_TaxRule_TestBase.php
index a721eaf5ed..22691105d3 100644
--- a/tests/class/helper/SC_Helper_TaxRule/SC_Helper_TaxRule_TestBase.php
+++ b/tests/class/helper/SC_Helper_TaxRule/SC_Helper_TaxRule_TestBase.php
@@ -28,7 +28,7 @@
  * @author Nobuhiko Kimoto
  * @version $Id$
  */
-class SC_Helper_TaxRule_TestBase extends Common_TestCase
+abstract class SC_Helper_TaxRule_TestBase extends Common_TestCase
 {
 
     /**
diff --git a/tests/class/helper/SC_Helper_TaxRule/SC_Helper_TaxRule_getTaxDetailTest.php b/tests/class/helper/SC_Helper_TaxRule/SC_Helper_TaxRule_getTaxDetailTest.php
new file mode 100644
index 0000000000..be84e71581
--- /dev/null
+++ b/tests/class/helper/SC_Helper_TaxRule/SC_Helper_TaxRule_getTaxDetailTest.php
@@ -0,0 +1,368 @@
+<?php
+require __DIR__.'/SC_Helper_TaxRule_TestBase.php';
+
+class SC_Helper_TaxRule_getDetailTest extends SC_Helper_TaxRule_TestBase
+{
+    private $taxs = [];
+    protected function setUp()
+    {
+        parent::setUp();
+    }
+
+    protected function tearDown()
+    {
+        parent::tearDown();
+    }
+
+    public function testGetTaxPerTaxRateWithRound()
+    {
+        $this->setUpTaxRule([
+            [
+                'tax_rule_id' => 1004,
+                'apply_date' => '2019-10-01 00:00:00',
+                'tax_rate' => '10',
+                'calc_rule' => '1',
+                'product_id' => '0',
+                'product_class_id' => '0',
+                'del_flg' => '0',
+                'member_id' => 1,
+                'create_date' => '2000-01-01 00:00:00',
+                'update_date' => '2000-01-01 00:00:00',
+            ],
+        ]);
+
+        $arrTaxableTotal = [
+            10 => 724431,
+            8 => 65756,
+        ];
+        $discount_total = 7159;
+
+        $actual = SC_Helper_TaxRule_Ex::getTaxPerTaxRate($arrTaxableTotal, $discount_total);
+        self::assertSame(
+            [
+                8 => [
+                    'discount' => 596,
+                    'total' => 65160,
+                    'tax' => 4827
+                ],
+                10 => [
+                    'discount' => 6563,
+                    'total' => 717868,
+                    'tax' => 65261
+                ]
+            ],
+            $actual
+        );
+
+        self::assertSame(
+            '(8%対象: 65,160円 内消費税: 4,827円)'.PHP_EOL.
+                '(10%対象: 717,868円 内消費税: 65,261円)'.PHP_EOL,
+            SC_Helper_TaxRule_Ex::getTaxDetail($arrTaxableTotal, $discount_total)
+        );
+    }
+
+    public function testGetTaxPerTaxRateWithZero()
+    {
+        $this->setUpTaxRule([
+            [
+                'tax_rule_id' => 1004,
+                'apply_date' => '2019-10-01 00:00:00',
+                'tax_rate' => '10',
+                'calc_rule' => '1',
+                'product_id' => '0',
+                'product_class_id' => '0',
+                'del_flg' => '0',
+                'member_id' => 1,
+                'create_date' => '2000-01-01 00:00:00',
+                'update_date' => '2000-01-01 00:00:00',
+            ],
+        ]);
+
+        $arrTaxableTotal = [
+            10 => 0,
+            8 => 0,
+        ];
+        $discount_total = 0;
+
+        $actual = SC_Helper_TaxRule_Ex::getTaxPerTaxRate($arrTaxableTotal, $discount_total);
+        self::assertSame(
+            [
+                8 => [
+                    'discount' => 0,
+                    'total' => 0,
+                    'tax' => 0
+                ],
+                10 => [
+                    'discount' => 0,
+                    'total' => 0,
+                    'tax' => 0
+                ]
+            ],
+            $actual
+        );
+
+        self::assertSame(
+            '(8%対象: 0円 内消費税: 0円)'.PHP_EOL.
+                '(10%対象: 0円 内消費税: 0円)'.PHP_EOL,
+            SC_Helper_TaxRule_Ex::getTaxDetail($arrTaxableTotal, $discount_total)
+        );
+    }
+
+    /**
+     * @runInSeparateProcess
+     * @preserveGlobalState disabled
+     */
+    public function testGetTaxPerTaxRateWithFloor()
+    {
+        self::markTestSkipped('Skip this test because @runInSeparateProcess does not work properly');
+
+        $this->setUpTaxRule([
+            [
+                'tax_rule_id' => 1004,
+                'apply_date' => '2019-10-01 00:00:00',
+                'tax_rate' => '10',
+                'calc_rule' => '2', // floor
+                'product_id' => '0',
+                'product_class_id' => '0',
+                'del_flg' => '0',
+                'member_id' => 1,
+                'create_date' => '2000-01-01 00:00:00',
+                'update_date' => '2000-01-01 00:00:00',
+            ],
+        ]);
+
+        $arrTaxableTotal = [
+            10 => 724431,
+            8 => 65756,
+        ];
+        $discount_total = 7159;
+
+        $actual = SC_Helper_TaxRule_Ex::getTaxPerTaxRate($arrTaxableTotal, $discount_total);
+        self::assertSame(
+            [
+                8 => [
+                    'discount' => 596,
+                    'total' => 65160,
+                    'tax' => 4826
+                ],
+                10 => [
+                    'discount' => 6563,
+                    'total' => 717868,
+                    'tax' => 65260
+                ]
+            ],
+            $actual
+        );
+
+        self::assertSame(array_sum($arrTaxableTotal) - $discount_total, $actual[8]['total'] + $actual[10]['total']);
+    }
+
+    /**
+     * @runInSeparateProcess
+     * @preserveGlobalState disabled
+     */
+    public function testGetTaxPerTaxRateWithCeil()
+    {
+        self::markTestSkipped('Skip this test because @runInSeparateProcess does not work properly');
+
+        $this->setUpTaxRule([
+            [
+                'tax_rule_id' => 1004,
+                'apply_date' => '2019-10-01 00:00:00',
+                'tax_rate' => '10',
+                'calc_rule' => '3', // ceil
+                'product_id' => '0',
+                'product_class_id' => '0',
+                'del_flg' => '0',
+                'member_id' => 1,
+                'create_date' => '2000-01-01 00:00:00',
+                'update_date' => '2000-01-01 00:00:00',
+            ],
+        ]);
+
+        $arrTaxableTotal = [
+            10 => 724431,
+            8 => 65756,
+        ];
+        $discount_total = 7159;
+
+        $actual = SC_Helper_TaxRule_Ex::getTaxPerTaxRate($arrTaxableTotal, $discount_total);
+        self::assertSame(
+            [
+                8 => [
+                    'discount' => 596,
+                    'total' => 65160,
+                    'tax' => 4827
+                ],
+                10 => [
+                    'discount' => 6563,
+                    'total' => 717868,
+                    'tax' => 65261
+                ]
+            ],
+            $actual
+        );
+
+        self::assertSame(array_sum($arrTaxableTotal) - $discount_total, $actual[8]['total'] + $actual[10]['total']);
+    }
+
+    /**
+     * @see https://github.com/EC-CUBE/ec-cube2/pull/762#issuecomment-1897799676
+     */
+    public function testGetTaxPerTaxRateWithRound2()
+    {
+        $this->setUpTaxRule([
+            [
+                'tax_rule_id' => 1004,
+                'apply_date' => '2019-10-01 00:00:00',
+                'tax_rate' => '10',
+                'calc_rule' => '1',
+                'product_id' => '0',
+                'product_class_id' => '0',
+                'del_flg' => '0',
+                'member_id' => 1,
+                'create_date' => '2000-01-01 00:00:00',
+                'update_date' => '2000-01-01 00:00:00',
+            ],
+        ]);
+
+        $arrTaxableTotal = [
+            10 => 1595,
+            8 => 7398,
+        ];
+        $discount_total = 92;
+
+        $actual = SC_Helper_TaxRule_Ex::getTaxPerTaxRate($arrTaxableTotal, $discount_total);
+        self::assertSame(
+            [
+                8 => [
+                    'discount' => 76,
+                    'total' => 7322,
+                    'tax' => 542
+                ],
+                10 => [
+                    'discount' => 16,
+                    'total' => 1579,
+                    'tax' => 144
+                ]
+            ],
+            $actual
+        );
+
+        self::assertSame(
+            '(8%対象: 7,322円 内消費税: 542円)'.PHP_EOL.
+                '(10%対象: 1,579円 内消費税: 144円)'.PHP_EOL,
+            SC_Helper_TaxRule_Ex::getTaxDetail($arrTaxableTotal, $discount_total)
+        );
+
+        self::assertSame(array_sum($arrTaxableTotal) - $discount_total, $actual[8]['total'] + $actual[10]['total']);
+    }
+
+    /**
+     * @see https://github.com/EC-CUBE/ec-cube2/pull/762#issuecomment-1897799676
+     * @runInSeparateProcess
+     * @preserveGlobalState disabled
+     */
+    public function testGetTaxPerTaxRateWithFloor2()
+    {
+        self::markTestSkipped('Skip this test because @runInSeparateProcess does not work properly');
+
+        $this->setUpTaxRule([
+            [
+                'tax_rule_id' => 1004,
+                'apply_date' => '2019-10-01 00:00:00',
+                'tax_rate' => '10',
+                'calc_rule' => '2', // floor
+                'product_id' => '0',
+                'product_class_id' => '0',
+                'del_flg' => '0',
+                'member_id' => 1,
+                'create_date' => '2000-01-01 00:00:00',
+                'update_date' => '2000-01-01 00:00:00',
+            ],
+        ]);
+
+        $arrTaxableTotal = [
+            10 => 1595,
+            8 => 7398,
+        ];
+        $discount_total = 92;
+
+        $actual = SC_Helper_TaxRule_Ex::getTaxPerTaxRate($arrTaxableTotal, $discount_total);
+        self::assertSame(
+            [
+                8 => [
+                    'discount' => 76,
+                    'total' => 7322,
+                    'tax' => 542
+                ],
+                10 => [
+                    'discount' => 16,
+                    'total' => 1579,
+                    'tax' => 143
+                ]
+            ],
+            $actual
+        );
+
+        self::assertSame(array_sum($arrTaxableTotal) - $discount_total, $actual[8]['total'] + $actual[10]['total']);
+    }
+
+    /**
+     * @see https://github.com/EC-CUBE/ec-cube2/pull/762#issuecomment-1897799676
+     * @runInSeparateProcess
+     * @preserveGlobalState disabled
+     */
+    public function testGetTaxPerTaxRateWithCeil2()
+    {
+        self::markTestSkipped('Skip this test because @runInSeparateProcess does not work properly');
+
+        $this->setUpTaxRule([
+            [
+                'tax_rule_id' => 1004,
+                'apply_date' => '2019-10-01 00:00:00',
+                'tax_rate' => '10',
+                'calc_rule' => '3', // ceil
+                'product_id' => '0',
+                'product_class_id' => '0',
+                'del_flg' => '0',
+                'member_id' => 1,
+                'create_date' => '2000-01-01 00:00:00',
+                'update_date' => '2000-01-01 00:00:00',
+            ],
+        ]);
+
+        $arrTaxableTotal = [
+            10 => 1595,
+            8 => 7398,
+        ];
+        $discount_total = 92;
+
+        $actual = SC_Helper_TaxRule_Ex::getTaxPerTaxRate($arrTaxableTotal, $discount_total);
+        self::assertSame(
+            [
+                8 => [
+                    'discount' => 76,
+                    'total' => 7322,
+                    'tax' => 543
+                ],
+                10 => [
+                    'discount' => 16,
+                    'total' => 1579,
+                    'tax' => 144
+                ]
+            ],
+            $actual
+        );
+
+        self::assertSame(array_sum($arrTaxableTotal) - $discount_total, $actual[8]['total'] + $actual[10]['total']);
+    }
+
+    protected function setUpTaxRule(array $taxs = [])
+    {
+        $this->objQuery->delete('dtb_tax_rule');
+        foreach ($taxs as $key => $item) {
+            $this->objQuery->insert('dtb_tax_rule', $item);
+        }
+    }
+}