diff --git a/html/.htaccess b/html/.htaccess
index b75d73c0c0..668bd6ec04 100644
--- a/html/.htaccess
+++ b/html/.htaccess
@@ -1,3 +1,9 @@
+<ifModule mod_headers.c>
+Header always set X-XSS-Protection "1; mode=block"
+Header always set X-Content-Type-Options "nosniff"
+Header always set X-Frame-Options DENY
+</ifModule>
+
 # 基本は SC_Initial.php で設定するが、ini_setで反映されないものはここで設定する
 <IfModule mod_php5.c>
 php_value mbstring.language Japanese