diff --git a/src/backend/browser/sandbox.ts b/src/backend/browser/sandbox.ts
index f2f5451085..b560131c4d 100644
--- a/src/backend/browser/sandbox.ts
+++ b/src/backend/browser/sandbox.ts
@@ -284,32 +284,15 @@ export const api: Sandbox = {
     // TODO: Impl
     return;
   },
-  async theme(newData?: string) {
-    if (newData != undefined) {
-      await this.setSetting("currentTheme", newData);
-      return;
-    }
+  async getAvailableThemes() {
     // NOTE: Electron版では起動時にテーマ情報が必要なので、
     //       この実装とは違って起動時に読み込んだキャッシュを返すだけになっている。
     return Promise.all(
       // FIXME: themeファイルのいい感じのパスの設定
       ["/themes/default.json", "/themes/dark.json"].map((url) =>
-        fetch(url).then((res) => res.json()),
+        fetch(url).then((res) => res.json() as Promise<ThemeConf>),
       ),
-    )
-      .then((v) => ({
-        currentTheme: "Default",
-        availableThemes: v,
-      }))
-      .then((v) =>
-        this.getSetting("currentTheme").then(
-          (currentTheme) =>
-            ({
-              ...v,
-              currentTheme,
-            }) as { currentTheme: string; availableThemes: ThemeConf[] },
-        ),
-      );
+    );
   },
   vuexReady() {
     // NOTE: 何もしなくて良さそう
diff --git a/src/backend/electron/main.ts b/src/backend/electron/main.ts
index 96b6ff18b4..97e5e7c16f 100644
--- a/src/backend/electron/main.ts
+++ b/src/backend/electron/main.ts
@@ -922,15 +922,8 @@ ipcMainHandle("HOTKEY_SETTINGS", (_, { newData }) => {
   return configManager.get("hotkeySettings");
 });
 
-ipcMainHandle("THEME", (_, { newData }) => {
-  if (newData != undefined) {
-    configManager.set("currentTheme", newData);
-    return;
-  }
-  return {
-    currentTheme: configManager.get("currentTheme"),
-    availableThemes: themes,
-  };
+ipcMainHandle("GET_AVAILABLE_THEMES", () => {
+  return themes;
 });
 
 ipcMainHandle("ON_VUEX_READY", () => {
diff --git a/src/backend/electron/preload.ts b/src/backend/electron/preload.ts
index d529909e2c..1168da7ac9 100644
--- a/src/backend/electron/preload.ts
+++ b/src/backend/electron/preload.ts
@@ -226,8 +226,8 @@ const api: Sandbox = {
     ipcRenderer.invoke("SET_NATIVE_THEME", source);
   },
 
-  theme: (newData) => {
-    return ipcRenderer.invoke("THEME", { newData });
+  getAvailableThemes: () => {
+    return ipcRenderer.invoke("GET_AVAILABLE_THEMES");
   },
 
   vuexReady: () => {
diff --git a/src/components/Dialog/SettingDialog/SettingDialog.vue b/src/components/Dialog/SettingDialog/SettingDialog.vue
index 75574e3a90..cf36c8b319 100644
--- a/src/components/Dialog/SettingDialog/SettingDialog.vue
+++ b/src/components/Dialog/SettingDialog/SettingDialog.vue
@@ -609,14 +609,14 @@ const isDefaultConfirmedTips = computed(() => {
 
 // 外観
 const currentThemeNameComputed = computed({
-  get: () => store.state.themeSetting.currentTheme,
+  get: () => store.state.currentTheme,
   set: (currentTheme: string) => {
-    store.dispatch("SET_THEME_SETTING", { currentTheme: currentTheme });
+    store.dispatch("SET_CURRENT_THEME_SETTING", { currentTheme });
   },
 });
 
 const availableThemeNameComputed = computed(() => {
-  return [...store.state.themeSetting.availableThemes]
+  return [...store.state.availableThemes]
     .sort((a, b) => a.order - b.order)
     .map((theme) => {
       return { label: theme.displayName, value: theme.name };
diff --git a/src/store/setting.ts b/src/store/setting.ts
index 6200c8fe44..de6d909095 100644
--- a/src/store/setting.ts
+++ b/src/store/setting.ts
@@ -7,7 +7,6 @@ import {
   SavingSetting,
   ExperimentalSettingType,
   ThemeColorType,
-  ThemeConf,
   ToolbarSettingType,
   EngineId,
   ConfirmedTips,
@@ -32,10 +31,8 @@ export const settingStoreState: SettingStoreState = {
   engineIds: [],
   engineInfos: {},
   engineManifests: {},
-  themeSetting: {
-    currentTheme: "Default",
-    availableThemes: [],
-  },
+  currentTheme: "Default",
+  availableThemes: [],
   editorFont: "default",
   showTextLineNumber: false,
   showAddAudioItemButton: true,
@@ -78,16 +75,12 @@ export const settingStore = createPartialStore<SettingStoreTypes>({
         });
       });
 
-      const theme = await window.backend.theme();
-      if (theme) {
-        commit("SET_THEME_SETTING", {
-          currentTheme: theme.currentTheme,
-          themes: theme.availableThemes,
-        });
-        dispatch("SET_THEME_SETTING", {
-          currentTheme: theme.currentTheme,
-        });
-      }
+      commit("SET_AVAILABLE_THEMES", {
+        themes: await window.backend.getAvailableThemes(),
+      });
+      dispatch("SET_CURRENT_THEME_SETTING", {
+        currentTheme: await window.backend.getSetting("currentTheme"),
+      });
 
       dispatch("SET_ACCEPT_RETRIEVE_TELEMETRY", {
         acceptRetrieveTelemetry: await window.backend.getSetting(
@@ -221,19 +214,13 @@ export const settingStore = createPartialStore<SettingStoreTypes>({
     },
   },
 
-  SET_THEME_SETTING: {
-    mutation(
-      state,
-      { currentTheme, themes }: { currentTheme: string; themes?: ThemeConf[] },
-    ) {
-      if (themes) {
-        state.themeSetting.availableThemes = themes;
-      }
-      state.themeSetting.currentTheme = currentTheme;
+  SET_CURRENT_THEME_SETTING: {
+    mutation(state, { currentTheme }: { currentTheme: string }) {
+      state.currentTheme = currentTheme;
     },
     action({ state, commit }, { currentTheme }: { currentTheme: string }) {
-      window.backend.theme(currentTheme);
-      const theme = state.themeSetting.availableThemes.find((value) => {
+      window.backend.setSetting("currentTheme", currentTheme);
+      const theme = state.availableThemes.find((value) => {
         return value.name == currentTheme;
       });
 
@@ -275,7 +262,7 @@ export const settingStore = createPartialStore<SettingStoreTypes>({
 
       window.backend.setNativeTheme(theme.isDark ? "dark" : "light");
 
-      commit("SET_THEME_SETTING", {
+      commit("SET_CURRENT_THEME_SETTING", {
         currentTheme: currentTheme,
       });
     },
diff --git a/src/store/type.ts b/src/store/type.ts
index b94864d7aa..40cc1506f3 100644
--- a/src/store/type.ts
+++ b/src/store/type.ts
@@ -29,7 +29,6 @@ import {
   MoraDataType,
   SavingSetting,
   ThemeConf,
-  ThemeSetting,
   ExperimentalSettingType,
   ToolbarSettingType,
   UpdateInfo,
@@ -1527,7 +1526,8 @@ export type SettingStoreState = {
   engineIds: EngineId[];
   engineInfos: Record<EngineId, EngineInfo>;
   engineManifests: Record<EngineId, EngineManifest>;
-  themeSetting: ThemeSetting;
+  currentTheme: string;
+  availableThemes: ThemeConf[];
   acceptTerms: AcceptTermsStatus;
   acceptRetrieveTelemetry: AcceptRetrieveTelemetryStatus;
   experimentalSetting: ExperimentalSettingType;
@@ -1568,8 +1568,8 @@ export type SettingStoreTypes = {
     action(payload: KeyValuePayload<RootMiscSettingType>): void;
   };
 
-  SET_THEME_SETTING: {
-    mutation: { currentTheme: string; themes?: ThemeConf[] };
+  SET_CURRENT_THEME_SETTING: {
+    mutation: { currentTheme: string };
     action(payload: { currentTheme: string }): void;
   };
 
@@ -1783,6 +1783,10 @@ export type UiStoreTypes = {
     action(payload: { activePointScrollMode: ActivePointScrollMode }): void;
   };
 
+  SET_AVAILABLE_THEMES: {
+    mutation: { themes: ThemeConf[] };
+  };
+
   DETECT_UNMAXIMIZED: {
     mutation: undefined;
     action(): void;
diff --git a/src/store/ui.ts b/src/store/ui.ts
index 59ac754d6d..e486f2cfa2 100644
--- a/src/store/ui.ts
+++ b/src/store/ui.ts
@@ -342,6 +342,12 @@ export const uiStore = createPartialStore<UiStoreTypes>({
     },
   },
 
+  SET_AVAILABLE_THEMES: {
+    mutation(state, { themes }) {
+      state.availableThemes = themes;
+    },
+  },
+
   DETECT_UNMAXIMIZED: {
     mutation(state) {
       state.isMaximized = false;
diff --git a/src/type/ipc.ts b/src/type/ipc.ts
index 599e4a717d..a001870444 100644
--- a/src/type/ipc.ts
+++ b/src/type/ipc.ts
@@ -244,9 +244,9 @@ export type IpcIHData = {
     return: ToolbarSettingType;
   };
 
-  THEME: {
-    args: [obj: { newData?: string }];
-    return: ThemeSetting | void;
+  GET_AVAILABLE_THEMES: {
+    args: [];
+    return: ThemeSetting;
   };
 
   ON_VUEX_READY: {
diff --git a/src/type/preload.ts b/src/type/preload.ts
index 01a3bdecb7..72ec8decf3 100644
--- a/src/type/preload.ts
+++ b/src/type/preload.ts
@@ -276,7 +276,7 @@ export interface Sandbox {
   getDefaultHotkeySettings(): Promise<HotkeySettingType[]>;
   getDefaultToolbarSetting(): Promise<ToolbarSettingType>;
   setNativeTheme(source: NativeThemeType): void;
-  theme(newData?: string): Promise<ThemeSetting | void>;
+  getAvailableThemes(): Promise<ThemeConf[]>;
   vuexReady(): void;
   getSetting<Key extends keyof ConfigType>(key: Key): Promise<ConfigType[Key]>;
   setSetting<Key extends keyof ConfigType>(
@@ -552,11 +552,6 @@ export type ThemeConf = {
   };
 };
 
-export type ThemeSetting = {
-  currentTheme: string;
-  availableThemes: ThemeConf[];
-};
-
 export const experimentalSettingSchema = z.object({
   enablePreset: z.boolean().default(false),
   shouldApplyDefaultPresetOnVoiceChanged: z.boolean().default(false),