diff --git a/packages/frontend/package.json b/packages/frontend/package.json
index 88b57e57ab..946a0be48f 100644
--- a/packages/frontend/package.json
+++ b/packages/frontend/package.json
@@ -75,7 +75,8 @@
 		"v-code-diff": "1.13.1",
 		"vite": "6.2.1",
 		"vue": "3.5.13",
-		"vuedraggable": "next"
+		"vuedraggable": "next",
+		"wanakana": "5.3.1"
 	},
 	"devDependencies": {
 		"@misskey-dev/summaly": "5.2.0",
diff --git a/packages/frontend/src/components/MkSuperMenu.vue b/packages/frontend/src/components/MkSuperMenu.vue
index d8dec3aa2f..ce0fa86219 100644
--- a/packages/frontend/src/components/MkSuperMenu.vue
+++ b/packages/frontend/src/components/MkSuperMenu.vue
@@ -6,16 +6,18 @@ SPDX-License-Identifier: AGPL-3.0-only
 <template>
 <div ref="rootEl" class="rrevdjwu" :class="{ grid }">
 	<MkInput
-		v-model="search"
+		v-if="searchIndex && searchIndex.length > 0"
+		v-model="searchQuery"
 		:placeholder="i18n.ts.search"
 		type="search"
 		style="margin-bottom: 16px;"
+		@input.passive="searchOnInput"
 		@keydown="searchOnKeyDown"
 	>
 		<template #prefix><i class="ti ti-search"></i></template>
 	</MkInput>
 
-	<template v-if="search == ''">
+	<template v-if="rawSearchQuery == ''">
 		<div v-for="group in def" class="group">
 			<div v-if="group.title" class="title">{{ group.title }}</div>
 
@@ -97,17 +99,22 @@ import MkInput from '@/components/MkInput.vue';
 import { i18n } from '@/i18n.js';
 import { getScrollContainer } from '@@/js/scroll.js';
 import { useRouter } from '@/router/supplier.js';
+import { initIntlString, compareStringIncludes } from '@/scripts/intl-string.js';
 
 const props = defineProps<{
 	def: SuperMenuDef[];
 	grid?: boolean;
-	searchIndex: SearchIndexItem[];
+	searchIndex?: SearchIndexItem[];
 }>();
 
+initIntlString();
+
 const router = useRouter();
 const rootEl = useTemplateRef('rootEl');
 
-const search = ref('');
+const searchQuery = ref('');
+const rawSearchQuery = ref('');
+
 const searchSelectedIndex = ref<null | number>(null);
 const searchResult = ref<{
 	id: string;
@@ -118,7 +125,11 @@ const searchResult = ref<{
 	parentLabels: string[];
 }[]>([]);
 
-watch(search, (value) => {
+watch(searchQuery, (value) => {
+	rawSearchQuery.value = value;
+});
+
+watch(rawSearchQuery, (value) => {
 	searchResult.value = [];
 	searchSelectedIndex.value = null;
 
@@ -128,14 +139,15 @@ watch(search, (value) => {
 
 	const dive = (items: SearchIndexItem[], parents: SearchIndexItem[] = []) => {
 		for (const item of items) {
-			const matched =
-				item.label.includes(value.toLowerCase()) ||
-				item.keywords.some((x) => x.toLowerCase().includes(value.toLowerCase()));
+			const matched = (
+				compareStringIncludes(item.label, value) ||
+				item.keywords.some((x) => compareStringIncludes(x, value))
+			);
 
 			if (matched) {
 				searchResult.value.push({
 					id: item.id,
-					path: item.path ?? parents.find((x) => x.path != null)?.path,
+					path: item.path ?? parents.find((x) => x.path != null)?.path ?? '/', // never gets `/`
 					label: item.label,
 					parentLabels: parents.map((x) => x.label).toReversed(),
 					icon: item.icon ?? parents.find((x) => x.icon != null)?.icon,
@@ -149,9 +161,16 @@ watch(search, (value) => {
 		}
 	};
 
-	dive(props.searchIndex);
+	if (props.searchIndex) {
+		dive(props.searchIndex);
+	}
 });
 
+function searchOnInput(ev: InputEvent) {
+	searchSelectedIndex.value = null;
+	rawSearchQuery.value = (ev.target as HTMLInputElement).value;
+}
+
 function searchOnKeyDown(ev: KeyboardEvent) {
 	if (ev.isComposing) return;
 
diff --git a/packages/frontend/src/scripts/intl-string.ts b/packages/frontend/src/scripts/intl-string.ts
new file mode 100644
index 0000000000..a5b5bbb592
--- /dev/null
+++ b/packages/frontend/src/scripts/intl-string.ts
@@ -0,0 +1,97 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { versatileLang } from '@@/js/intl-const.js';
+import type { toHiragana as toHiraganaType } from 'wanakana';
+
+let toHiragana: typeof toHiraganaType = (str?: string) => str ?? '';
+let isWanakanaLoaded = false;
+
+/** 
+ * ローマ字変換のセットアップ（日本語以外の環境で読み込まないのでlazy-loading）
+ * 
+ * ここの比較系関数を使う際は事前に呼び出す必要がある
+ */
+export async function initIntlString(forceWanakana = false) {
+	if ((!versatileLang.includes('ja') && !forceWanakana) || isWanakanaLoaded) return;
+	const { toHiragana: _toHiragana } = await import('wanakana');
+	toHiragana = _toHiragana;
+	isWanakanaLoaded = true;
+}
+
+/**
+ * - 全角英数字を半角に
+ * - 半角カタカナを全角に
+ * - 濁点・半濁点がリガチャになっている（例: `か` ＋ `゛` ）ひらがな・カタカナを結合
+ * - 異体字を正規化
+ * - 小文字に揃える
+ * - 文字列のトリム
+ */
+export function normalizeString(str: string) {
+	const segmenter = new Intl.Segmenter(versatileLang, { granularity: 'grapheme' });
+	return [...segmenter.segment(str)].map(({ segment }) => segment.normalize('NFKC')).join('').toLowerCase().trim();
+}
+
+// https://qiita.com/non-caffeine/items/77360dda05c8ce510084
+const hyphens = [
+	0x002d, // hyphen-minus
+	0x02d7, // modifier letter minus sign
+	0x1173, // hangul jongseong eu
+	0x1680, // ogham space mark
+	0x1b78, // balinese musical symbol left-hand open pang
+	0x2010, // hyphen
+	0x2011, // non-breaking hyphen
+	0x2012, // figure dash
+	0x2013, // en dash
+	0x2014, // em dash
+	0x2015, // horizontal bar
+	0x2043, // hyphen bullet
+	0x207b, // superscript minus
+	0x2212, // minus sign
+	0x25ac, // black rectangle
+	0x2500, // box drawings light horizontal
+	0x2501, // box drawings heavy horizontal
+	0x2796, // heavy minus sign
+	0x30fc, // katakana-hiragana prolonged sound mark
+	0x3161, // hangul letter eu
+	0xfe58, // small em dash
+	0xfe63, // small hyphen-minus
+	0xff0d, // fullwidth hyphen-minus
+	0xff70, // halfwidth katakana-hiragana prolonged sound mark
+	0x10110, // aegean number ten
+	0x10191, // roman uncia sign
+];
+
+const hyphensCodePoints = hyphens.map(code => `\\u{${code.toString(16).padStart(4, '0')}}`);
+
+/** ハイフンを統一（ローマ字半角入力時に`ー`と`-`が判定できない問題の調整） */
+export function normalizeHyphens(str: string) {
+	return str.replace(new RegExp(`[${hyphensCodePoints.join('')}]`, 'ug'), '\u002d');
+}
+
+/**
+ * `normalizeString` に加えて、カタカナ・ローマ字をひらがなに揃え、ハイフンを統一
+ *
+ * （ローマ字じゃないものもローマ字として認識され変換されるので、文字列比較の際は `normalizeString` を併用する必要あり）
+ */
+export function normalizeStringWithHiragana(str: string) {
+	return normalizeHyphens(toHiragana(normalizeString(str), { convertLongVowelMark: false }));
+}
+
+/** aとbが同じかどうか */
+export function compareStringEquals(a: string, b: string) {
+	return (
+		normalizeString(a) === normalizeString(b) ||
+		normalizeStringWithHiragana(a) === normalizeStringWithHiragana(b)
+	);
+}
+
+/** baseにqueryが含まれているかどうか */
+export function compareStringIncludes(base: string, query: string) {
+	return (
+		normalizeString(base).includes(normalizeString(query)) ||
+		normalizeStringWithHiragana(base).includes(normalizeStringWithHiragana(query))
+	);
+}
diff --git a/packages/frontend/test/intl-string.test.ts b/packages/frontend/test/intl-string.test.ts
new file mode 100644
index 0000000000..dd545b45d1
--- /dev/null
+++ b/packages/frontend/test/intl-string.test.ts
@@ -0,0 +1,142 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { assert, beforeEach, describe, test } from 'vitest';
+import {
+	normalizeString,
+	initIntlString,
+	normalizeStringWithHiragana,
+	compareStringEquals,
+	compareStringIncludes,
+} from '@/scripts/intl-string.js';
+
+// 共通のテストを実行するヘルパー関数
+const runCommonTests = (normalizeFn: (str: string) => string) => {
+	test('全角英数字が半角の小文字になる', () => {
+		// ローマ字にならないようにする
+		const input = 'Ｂ１２３';
+		const expected = 'b123';
+		assert.strictEqual(normalizeFn(input), expected);
+	});
+	test('濁点・半濁点が正しく結合される', () => {
+		const input = 'か\u3099';
+		const expected = 'が';
+		assert.strictEqual(normalizeFn(input), expected);
+	});
+	test('小文字に揃う', () => {
+		// ローマ字にならないようにする
+		const input = 'tSt';
+		const expected = 'tst';
+		assert.strictEqual(normalizeFn(input), expected);
+	});
+	test('文字列の前後の空白が削除される', () => {
+		const input = '   tst   ';
+		const expected = 'tst';
+		assert.strictEqual(normalizeFn(input), expected);
+	});
+};
+
+describe('normalize string', () => {
+	runCommonTests(normalizeString);
+
+	test('異体字の正規化 (ligature)', () => {
+		const input = 'fi';
+		const expected = 'fi';
+		assert.strictEqual(normalizeString(input), expected);
+	});
+
+	test('半角カタカナは全角に変換される', () => {
+		const input = 'ｶﾀｶﾅ';
+		const expected = 'カタカナ';
+		assert.strictEqual(normalizeString(input), expected);
+	});
+});
+
+// normalizeStringWithHiraganaのテスト
+describe('normalize string with hiragana', () => {
+	beforeEach(async () => {
+		await initIntlString(true);
+	});
+
+	// 共通テスト
+	describe('共通のnormalizeStringテスト', () => {
+		runCommonTests(normalizeStringWithHiragana);
+	});
+
+	test('半角カタカナがひらがなに変換される', () => {
+		const input = 'ｶﾀｶﾅ';
+		const expected = 'かたかな';
+		assert.strictEqual(normalizeStringWithHiragana(input), expected);
+	});
+
+	// normalizeStringWithHiragana特有のテスト
+	test('カタカナがひらがなに変換される・伸ばし棒はハイフンに変換される', () => {
+		const input = 'カタカナひーらがーな';
+		const expected = 'かたかなひ-らが-な';
+		assert.strictEqual(normalizeStringWithHiragana(input), expected);
+	});
+
+	test('ローマ字がひらがなに変換される', () => {
+		const input = 'ro-majimohiragananinarimasu';
+		const expected = 'ろ-まじもひらがなになります';
+		assert.strictEqual(normalizeStringWithHiragana(input), expected);
+	});
+});
+
+describe('compareStringEquals', () => {
+	beforeEach(async () => {
+		await initIntlString(true);
+	});
+
+	test('完全一致ならtrue', () => {
+		assert.isTrue(compareStringEquals('テスト', 'テスト'));
+	});
+
+	test('大文字・小文字の違いを無視', () => {
+		assert.isTrue(compareStringEquals('TeSt', 'test'));
+	});
+
+	test('全角・半角の違いを無視', () => {
+		assert.isTrue(compareStringEquals('ＡＢＣ', 'abc'));
+	});
+
+	test('カタカナとひらがなの違いを無視', () => {
+		assert.isTrue(compareStringEquals('カタカナ', 'かたかな'));
+	});
+
+	test('ローマ字をひらがなと比較可能', () => {
+		assert.isTrue(compareStringEquals('hiragana', 'ひらがな'));
+	});
+
+	test('異なる文字列はfalse', () => {
+		assert.isFalse(compareStringEquals('テスト', 'サンプル'));
+	});
+});
+
+describe('compareStringIncludes', () => {
+	test('部分一致ならtrue', () => {
+		assert.isTrue(compareStringIncludes('これはテストです', 'テスト'));
+	});
+
+	test('大文字・小文字の違いを無視', () => {
+		assert.isTrue(compareStringIncludes('This is a Test', 'test'));
+	});
+
+	test('全角・半角の違いを無視', () => {
+		assert.isTrue(compareStringIncludes('ＡＢＣＤＥ', 'abc'));
+	});
+
+	test('カタカナとひらがなの違いを無視', () => {
+		assert.isTrue(compareStringIncludes('カタカナのテスト', 'かたかな'));
+	});
+
+	test('ローマ字をひらがなと比較可能', () => {
+		assert.isTrue(compareStringIncludes('これはhiraganaのテスト', 'ひらがな'));
+	});
+
+	test('異なる文字列はfalse', () => {
+		assert.isFalse(compareStringIncludes('これはテストです', 'サンプル'));
+	});
+});
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 4d11b5ac49..46ce2bf978 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -874,6 +874,9 @@ importers:
       vuedraggable:
         specifier: next
         version: 4.1.0(vue@3.5.13(typescript@5.8.2))
+      wanakana:
+        specifier: 5.3.1
+        version: 5.3.1
     devDependencies:
       '@misskey-dev/summaly':
         specifier: 5.2.0
@@ -10563,6 +10566,10 @@ packages:
   walker@1.0.8:
     resolution: {integrity: sha512-ts/8E8l5b7kY0vlWLewOkDXMmPdLcVV4GmOQLyxuSswIJsweeFZtAsMF7k1Nszz+TYBQrlYRmzOnr398y1JemQ==}
 
+  wanakana@5.3.1:
+    resolution: {integrity: sha512-OSDqupzTlzl2LGyqTdhcXcl6ezMiFhcUwLBP8YKaBIbMYW1wAwDvupw2T9G9oVaKT9RmaSpyTXjxddFPUcFFIw==}
+    engines: {node: '>=12'}
+
   web-push@3.6.7:
     resolution: {integrity: sha512-OpiIUe8cuGjrj3mMBFWY+e4MMIkW3SVT+7vEIjvD9kejGUypv8GPDf84JdPWskK8zMRIJ6xYGm+Kxr8YkPyA0A==}
     engines: {node: '>= 16'}
@@ -22026,6 +22033,8 @@ snapshots:
     dependencies:
       makeerror: 1.0.12
 
+  wanakana@5.3.1: {}
+
   web-push@3.6.7:
     dependencies:
       asn1.js: 5.4.1