diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1f65f6278822c089a88116ee22f9cf85e34b153d..199a420f7bfff2b9f834ec6071281f74122289e9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,8 +19,9 @@
 - Fix: 自分のdirect noteがuser list timelineに追加されない
 
 ### Client
-- Fix: 一部のモデログ(logYellowでの表示対象)について、表示の色が変わらない問題を修正
 - Feat: AiScript専用のMFM構文`$[clickable.ev=EVENTNAME ...]`を追加。`Mk:C:mfm`のオプション`onClickEv`に関数を渡すと、クリック時に`EVENTNAME`を引数にして呼び出す
+- Enhance: MFM入力補助ボタンを投稿フォームに表示できるように #12787
+- Fix: 一部のモデログ(logYellowでの表示対象)について、表示の色が変わらない問題を修正
 - Fix: `fg`/`bg`MFMに長い単語を指定すると、オーバーフローされずはみ出る問題を修正
 
 ### Server
diff --git a/locales/index.d.ts b/locales/index.d.ts
index 89bdddbdcf93a3630ee9246e570ec75ea3ec60f0..60e88a219240b22aa0bbc36cedcb32213a7e374a 100644
--- a/locales/index.d.ts
+++ b/locales/index.d.ts
@@ -1184,6 +1184,8 @@ export interface Locale {
     "overwriteContentConfirm": string;
     "seasonalScreenEffect": string;
     "decorate": string;
+    "addMfmFunction": string;
+    "enableQuickAddMfmFunction": string;
     "_announcement": {
         "forExistingUsers": string;
         "forExistingUsersDescription": string;
diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index 7bc5889297bbd5f35fdea2ce93b4fffc5e70353f..3d31dcef4954f7161d6d1ace15da8146f42dd290 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -1181,6 +1181,8 @@ remainingN: "残り: {n}"
 overwriteContentConfirm: "現在の内容に上書きされますがよろしいですか？"
 seasonalScreenEffect: "季節に応じた画面の演出"
 decorate: "デコる"
+addMfmFunction: "装飾を追加"
+enableQuickAddMfmFunction: "高度なMFMのピッカーを表示する"
 
 _announcement:
   forExistingUsers: "既存ユーザーのみ"
diff --git a/packages/frontend/src/components/MkPostForm.vue b/packages/frontend/src/components/MkPostForm.vue
index 5e7ca5539ec95b0f224ac6c57684d5814462497e..3aacf4c2da01ba4e322192f9ce73db083d754050 100644
--- a/packages/frontend/src/components/MkPostForm.vue
+++ b/packages/frontend/src/components/MkPostForm.vue
@@ -86,6 +86,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 			<button v-tooltip="i18n.ts.hashtags" class="_button" :class="[$style.footerButton, { [$style.footerButtonActive]: withHashtags }]" @click="withHashtags = !withHashtags"><i class="ti ti-hash"></i></button>
 			<button v-if="postFormActions.length > 0" v-tooltip="i18n.ts.plugin" class="_button" :class="$style.footerButton" @click="showActions"><i class="ti ti-plug"></i></button>
 			<button v-tooltip="i18n.ts.emoji" :class="['_button', $style.footerButton]" @click="insertEmoji"><i class="ti ti-mood-happy"></i></button>
+			<button v-if="showAddMfmFunction" v-tooltip="i18n.ts.addMfmFunction" :class="['_button', $style.footerButton]" @click="insertMfmFunction"><i class="ti ti-palette"></i></button>
 		</div>
 		<div :class="$style.footerRight">
 			<button v-tooltip="i18n.ts.previewNoteText" class="_button" :class="[$style.footerButton, { [$style.previewButtonActive]: showPreview }]" @click="showPreview = !showPreview"><i class="ti ti-eye"></i></button>
@@ -126,6 +127,7 @@ import MkRippleEffect from '@/components/MkRippleEffect.vue';
 import { miLocalStorage } from '@/local-storage.js';
 import { claimAchievement } from '@/scripts/achievements.js';
 import { emojiPicker } from '@/scripts/emoji-picker.js';
+import { mfmFunctionPicker } from '@/scripts/mfm-function-picker.js';
 
 const modal = inject('modal');
 
@@ -182,6 +184,8 @@ const poll = ref<{
 const useCw = ref<boolean>(!!props.initialCw);
 const showPreview = ref(defaultStore.state.showPreview);
 watch(showPreview, () => defaultStore.set('showPreview', showPreview.value));
+const showAddMfmFunction = ref(defaultStore.state.enableQuickAddMfmFunction);
+watch(showAddMfmFunction, () => defaultStore.set('enableQuickAddMfmFunction', showAddMfmFunction.value));
 const cw = ref<string | null>(props.initialCw ?? null);
 const localOnly = ref<boolean>(props.initialLocalOnly ?? defaultStore.state.rememberNoteVisibility ? defaultStore.state.localOnly : defaultStore.state.defaultNoteLocalOnly);
 const visibility = ref(props.initialVisibility ?? (defaultStore.state.rememberNoteVisibility ? defaultStore.state.visibility : defaultStore.state.defaultNoteVisibility) as typeof Misskey.noteVisibilities[number]);
@@ -863,6 +867,14 @@ async function insertEmoji(ev: MouseEvent) {
 	);
 }
 
+async function insertMfmFunction(ev: MouseEvent) {
+	mfmFunctionPicker(
+		ev.currentTarget ?? ev.target,
+		textareaEl.value,
+		text,
+	);
+}
+
 function showActions(ev) {
 	os.popupMenu(postFormActions.map(action => ({
 		text: action.title,
diff --git a/packages/frontend/src/pages/settings/general.vue b/packages/frontend/src/pages/settings/general.vue
index 826ede17e5c7ff4aab8c88859a7d7bd28201e04c..3e5f5cb8c8f029663f669585862531e5dc0850be 100644
--- a/packages/frontend/src/pages/settings/general.vue
+++ b/packages/frontend/src/pages/settings/general.vue
@@ -48,6 +48,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 				<MkSwitch v-model="collapseRenotes">{{ i18n.ts.collapseRenotes }}</MkSwitch>
 				<MkSwitch v-model="advancedMfm">{{ i18n.ts.enableAdvancedMfm }}</MkSwitch>
 				<MkSwitch v-if="advancedMfm" v-model="animatedMfm">{{ i18n.ts.enableAnimatedMfm }}</MkSwitch>
+				<MkSwitch v-if="advancedMfm" v-model="enableQuickAddMfmFunction">{{ i18n.ts.enableQuickAddMfmFunction }}</MkSwitch>
 				<MkSwitch v-model="showGapBetweenNotesInTimeline">{{ i18n.ts.showGapBetweenNotesInTimeline }}</MkSwitch>
 				<MkSwitch v-model="loadRawImages">{{ i18n.ts.loadRawImages }}</MkSwitch>
 				<MkRadios v-model="reactionsDisplaySize">
@@ -268,6 +269,7 @@ const useBlurEffect = computed(defaultStore.makeGetterSetter('useBlurEffect'));
 const showGapBetweenNotesInTimeline = computed(defaultStore.makeGetterSetter('showGapBetweenNotesInTimeline'));
 const animatedMfm = computed(defaultStore.makeGetterSetter('animatedMfm'));
 const advancedMfm = computed(defaultStore.makeGetterSetter('advancedMfm'));
+const enableQuickAddMfmFunction = computed(defaultStore.makeGetterSetter('enableQuickAddMfmFunction'));
 const emojiStyle = computed(defaultStore.makeGetterSetter('emojiStyle'));
 const disableDrawer = computed(defaultStore.makeGetterSetter('disableDrawer'));
 const disableShowingAnimatedImages = computed(defaultStore.makeGetterSetter('disableShowingAnimatedImages'));
diff --git a/packages/frontend/src/scripts/mfm-function-picker.ts b/packages/frontend/src/scripts/mfm-function-picker.ts
new file mode 100644
index 0000000000000000000000000000000000000000..465926fe044522db315c239edc96d581f44b5c7e
--- /dev/null
+++ b/packages/frontend/src/scripts/mfm-function-picker.ts
@@ -0,0 +1,61 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and other misskey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { Ref, nextTick } from 'vue';
+import * as os from '@/os.js';
+import { i18n } from '@/i18n.js';
+import { MFM_TAGS } from '@/const.js';
+
+/**
+ * MFMの装飾のリストを表示する
+ */
+export function mfmFunctionPicker(src: any, textArea: HTMLInputElement | HTMLTextAreaElement, textRef: Ref<string>) {
+	return new Promise((res, rej) => {
+		os.popupMenu([{
+			text: i18n.ts.addMfmFunction,
+			type: 'label',
+		}, ...getFunctionList(textArea, textRef)], src);
+	});
+}
+
+function getFunctionList(textArea: HTMLInputElement | HTMLTextAreaElement, textRef: Ref<string>) : object[] {
+	const ret: object[] = [];
+	MFM_TAGS.forEach(tag => {
+		ret.push({
+			text: tag,
+			icon: 'ti ti-icons',
+			action: () => add(textArea, textRef, tag),
+		});
+	});
+	return ret;
+}
+
+function add(textArea: HTMLInputElement | HTMLTextAreaElement, textRef: Ref<string>, type: string) {
+	const caretStart: number = textArea.selectionStart as number;
+	const caretEnd: number = textArea.selectionEnd as number;
+
+	MFM_TAGS.forEach(tag => {
+		if (type === tag) {
+			if (caretStart === caretEnd) {
+				// 単純にFunctionを追加
+				const trimmedText = `${textRef.value.substring(0, caretStart)}$[${type} ]${textRef.value.substring(caretEnd)}`;
+				textRef.value = trimmedText;
+			} else {
+				// 選択範囲を囲むようにFunctionを追加
+				const trimmedText = `${textRef.value.substring(0, caretStart)}$[${type} ${textRef.value.substring(caretStart, caretEnd)}]${textRef.value.substring(caretEnd)}`;
+				textRef.value = trimmedText;
+			}
+		}
+	});
+
+	const nextCaretStart: number = caretStart + 3 + type.length;
+	const nextCaretEnd: number = caretEnd + 3 + type.length;
+
+	// キャレットを戻す
+	nextTick(() => {
+		textArea.focus();
+		textArea.setSelectionRange(nextCaretStart, nextCaretEnd);
+	});
+}
diff --git a/packages/frontend/src/store.ts b/packages/frontend/src/store.ts
index 3f8a5f5a6f3942c4f726f8a92d3905599dc5fae5..46634af96b0a334dd7964cac834b42e873f68427 100644
--- a/packages/frontend/src/store.ts
+++ b/packages/frontend/src/store.ts
@@ -219,6 +219,10 @@ export const defaultStore = markRaw(new Storage('base', {
 		where: 'device',
 		default: true,
 	},
+	enableQuickAddMfmFunction: {
+		where: 'device',
+		default: false,
+	},
 	loadRawImages: {
 		where: 'device',
 		default: false,