diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index 29bd5da9e..8974976e1 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -128,6 +128,10 @@ common:
   reduce-motion: "UIの動きを減らす"
   this-setting-is-this-device-only: "このデバイスのみ"
   use-os-default-emojis: "OS標準の絵文字を使用"
+  line-width: "線の太さ"
+  line-width-thin: "細い"
+  line-width-normal: "普通"
+  line-width-thick: "太い"
 
   do-not-use-in-production: "これは開発ビルドです。本番環境で使用しないでください。"
   user-suspended: "このユーザーは凍結されています。"
@@ -878,10 +882,6 @@ desktop/views/components/settings.vue:
   dark-mode: "ダークモード"
   use-shadow: "UIに影を使用"
   rounded-corners: "UIの角を丸める"
-  line-width: "線の太さ"
-  line-width-thin: "細い"
-  line-width-normal: "普通"
-  line-width-thick: "太い"
   circle-icons: "円形のアイコンを使用"
   contrasted-acct: "ユーザー名にコントラストを付ける"
   post-form-on-timeline: "タイムライン上部に投稿フォームを表示する"
diff --git a/src/client/app/desktop/views/components/settings.vue b/src/client/app/desktop/views/components/settings.vue
index 45367c743..676dfe670 100644
--- a/src/client/app/desktop/views/components/settings.vue
+++ b/src/client/app/desktop/views/components/settings.vue
@@ -100,10 +100,10 @@
 				<ui-switch v-model="roundedCorners">{{ $t('rounded-corners') }}</ui-switch>
 				<ui-switch v-model="circleIcons">{{ $t('circle-icons') }}</ui-switch>
 				<section>
-					<header>{{ $t('line-width') }}</header>
-					<ui-radio v-model="lineWidth" :value="0.5">{{ $t('line-width-thin') }}</ui-radio>
-					<ui-radio v-model="lineWidth" :value="1">{{ $t('line-width-normal') }}</ui-radio>
-					<ui-radio v-model="lineWidth" :value="2">{{ $t('line-width-thick') }}</ui-radio>
+					<header>{{ $t('@.line-width') }}</header>
+					<ui-radio v-model="lineWidth" :value="0.5">{{ $t('@.line-width-thin') }}</ui-radio>
+					<ui-radio v-model="lineWidth" :value="1">{{ $t('@.line-width-normal') }}</ui-radio>
+					<ui-radio v-model="lineWidth" :value="2">{{ $t('@.line-width-thick') }}</ui-radio>
 				</section>
 				<ui-switch v-model="reduceMotion">{{ $t('@.reduce-motion') }}</ui-switch>
 				<ui-switch v-model="contrastedAcct">{{ $t('contrasted-acct') }}</ui-switch>
diff --git a/src/client/app/mobile/views/pages/settings.vue b/src/client/app/mobile/views/pages/settings.vue
index 87db25721..e37291247 100644
--- a/src/client/app/mobile/views/pages/settings.vue
+++ b/src/client/app/mobile/views/pages/settings.vue
@@ -15,6 +15,12 @@
 				<section>
 					<ui-switch v-model="darkmode">{{ $t('dark-mode') }}</ui-switch>
 					<ui-switch v-model="circleIcons">{{ $t('circle-icons') }}</ui-switch>
+					<section>
+						<header>{{ $t('@.line-width') }}</header>
+						<ui-radio v-model="lineWidth" :value="0.5">{{ $t('@.line-width-thin') }}</ui-radio>
+						<ui-radio v-model="lineWidth" :value="1">{{ $t('@.line-width-normal') }}</ui-radio>
+						<ui-radio v-model="lineWidth" :value="2">{{ $t('@.line-width-thick') }}</ui-radio>
+					</section>
 					<ui-switch v-model="reduceMotion">{{ $t('@.reduce-motion') }} ({{ $t('@.this-setting-is-this-device-only') }})</ui-switch>
 					<ui-switch v-model="contrastedAcct">{{ $t('contrasted-acct') }}</ui-switch>
 					<ui-switch v-model="showFullAcct">{{ $t('@.show-full-acct') }}</ui-switch>
@@ -260,6 +266,11 @@ export default Vue.extend({
 			set(value) { this.$store.dispatch('settings/set', { key: 'circleIcons', value }); }
 		},
 
+		lineWidth: {
+			get() { return this.$store.state.settings.lineWidth; },
+			set(value) { this.$store.dispatch('settings/set', { key: 'lineWidth', value }); }
+		},
+
 		contrastedAcct: {
 			get() { return this.$store.state.settings.contrastedAcct; },
 			set(value) { this.$store.dispatch('settings/set', { key: 'contrastedAcct', value }); }