diff --git a/CHANGELOG.md b/CHANGELOG.md
index 63bf42c72..cb4a17d95 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -87,6 +87,7 @@
 - Fix: properly handle cc followers
 - Fix: ジョブに関する設定の名前を修正 relashionshipJobPerSec -> relationshipJobPerSec
 - Fix: コントロールパネル->モデレーション->「誰でも新規登録できるようにする」の初期値をONからOFFに変更 #13122
+- Enhance: 連合向けのノート配信を軽量化 #13192
 
 ### Service Worker
 - Enhance: オフライン表示のデザインを改善・多言語対応
diff --git a/packages/backend/src/core/MfmService.ts b/packages/backend/src/core/MfmService.ts
index e74c62e1a..b2d8382bf 100644
--- a/packages/backend/src/core/MfmService.ts
+++ b/packages/backend/src/core/MfmService.ts
@@ -419,6 +419,10 @@ export class MfmService {
 			},
 
 			text: (node) => {
+				if (!node.props.text.match(/[\r\n]/)) {
+					return doc.createTextNode(node.props.text);
+				}
+
 				const el = doc.createElement('span');
 				const nodes = node.props.text.split(/\r\n|\r|\n/).map(x => doc.createTextNode(x));
 
diff --git a/packages/backend/src/core/activitypub/ApMfmService.ts b/packages/backend/src/core/activitypub/ApMfmService.ts
index 60868627a..737c34f3c 100644
--- a/packages/backend/src/core/activitypub/ApMfmService.ts
+++ b/packages/backend/src/core/activitypub/ApMfmService.ts
@@ -25,8 +25,21 @@ export class ApMfmService {
 	}
 
 	@bindThis
-	public getNoteHtml(note: MiNote): string | null {
-		if (!note.text) return '';
-		return this.mfmService.toHtml(mfm.parse(note.text), JSON.parse(note.mentionedRemoteUsers));
+	public getNoteHtml(note: MiNote, apAppend?: string) {
+		let noMisskeyContent = false;
+		const srcMfm = (note.text ?? '') + (apAppend ?? '');
+
+		const parsed = mfm.parse(srcMfm);
+
+		if (!apAppend && parsed?.every(n => ['text', 'unicodeEmoji', 'emojiCode', 'mention', 'hashtag', 'url'].includes(n.type))) {
+			noMisskeyContent = true;
+		}
+
+		const content = this.mfmService.toHtml(parsed, JSON.parse(note.mentionedRemoteUsers));
+
+		return {
+			content,
+			noMisskeyContent,
+		};
 	}
 }
diff --git a/packages/backend/src/core/activitypub/ApRendererService.ts b/packages/backend/src/core/activitypub/ApRendererService.ts
index 530e4a3c3..211f4f4a4 100644
--- a/packages/backend/src/core/activitypub/ApRendererService.ts
+++ b/packages/backend/src/core/activitypub/ApRendererService.ts
@@ -389,17 +389,15 @@ export class ApRendererService {
 			poll = await this.pollsRepository.findOneBy({ noteId: note.id });
 		}
 
-		let apText = text;
+		let apAppend = '';
 
 		if (quote) {
-			apText += `\n\nRE: ${quote}`;
+			apAppend += `\n\nRE: ${quote}`;
 		}
 
 		const summary = note.cw === '' ? String.fromCharCode(0x200B) : note.cw;
 
-		const content = this.apMfmService.getNoteHtml(Object.assign({}, note, {
-			text: apText,
-		}));
+		const { content, noMisskeyContent } = this.apMfmService.getNoteHtml(note, apAppend);
 
 		const emojis = await this.getEmojis(note.emojis);
 		const apemojis = emojis.filter(emoji => !emoji.localOnly).map(emoji => this.renderEmoji(emoji));
@@ -412,9 +410,6 @@ export class ApRendererService {
 
 		const asPoll = poll ? {
 			type: 'Question',
-			content: this.apMfmService.getNoteHtml(Object.assign({}, note, {
-				text: text,
-			})),
 			[poll.expiresAt && poll.expiresAt < new Date() ? 'closed' : 'endTime']: poll.expiresAt,
 			[poll.multiple ? 'anyOf' : 'oneOf']: poll.choices.map((text, i) => ({
 				type: 'Note',
@@ -432,11 +427,13 @@ export class ApRendererService {
 			attributedTo,
 			summary: summary ?? undefined,
 			content: content ?? undefined,
-			_misskey_content: text,
-			source: {
-				content: text,
-				mediaType: 'text/x.misskeymarkdown',
-			},
+			...(noMisskeyContent ? {} : {
+				_misskey_content: text,
+				source: {
+					content: text,
+					mediaType: 'text/x.misskeymarkdown',
+				},
+			}),
 			_misskey_quote: quote,
 			quoteUrl: quote,
 			published: this.idService.parse(note.id).date.toISOString(),
diff --git a/packages/backend/test/unit/ApMfmService.ts b/packages/backend/test/unit/ApMfmService.ts
new file mode 100644
index 000000000..2b79041c8
--- /dev/null
+++ b/packages/backend/test/unit/ApMfmService.ts
@@ -0,0 +1,44 @@
+import * as assert from 'assert';
+import { Test } from '@nestjs/testing';
+
+import { CoreModule } from '@/core/CoreModule.js';
+import { ApMfmService } from '@/core/activitypub/ApMfmService.js';
+import { GlobalModule } from '@/GlobalModule.js';
+import { MiNote } from '@/models/Note.js';
+
+describe('ApMfmService', () => {
+	let apMfmService: ApMfmService;
+
+	beforeAll(async () => {
+		const app = await Test.createTestingModule({
+			imports: [GlobalModule, CoreModule],
+		}).compile();
+		apMfmService = app.get<ApMfmService>(ApMfmService);
+	});
+
+	describe('getNoteHtml', () => {
+		test('Do not provide _misskey_content for simple text', () => {
+			const note: MiNote = {
+				text: 'テキスト #タグ @mention 🍊 :emoji: https://example.com',
+				mentionedRemoteUsers: '[]',
+			} as any;
+
+			const { content, noMisskeyContent } = apMfmService.getNoteHtml(note);
+
+			assert.equal(noMisskeyContent, true, 'noMisskeyContent');
+			assert.equal(content, '<p>テキスト <a href="http://misskey.local/tags/タグ" rel="tag">#タグ</a> <a href="http://misskey.local/@mention" class="u-url mention">@mention</a> 🍊 ​:emoji:​ <a href="https://example.com">https://example.com</a></p>', 'content');
+		});
+
+		test('Provide _misskey_content for MFM', () => {
+			const note: MiNote = {
+				text: '$[tada foo]',
+				mentionedRemoteUsers: '[]',
+			} as any;
+
+			const { content, noMisskeyContent } = apMfmService.getNoteHtml(note);
+
+			assert.equal(noMisskeyContent, false, 'noMisskeyContent');
+			assert.equal(content, '<p><i>foo</i></p>', 'content');
+		});
+	});
+});
diff --git a/packages/backend/test/unit/MfmService.ts b/packages/backend/test/unit/MfmService.ts
index bb8e6981d..c3827b20d 100644
--- a/packages/backend/test/unit/MfmService.ts
+++ b/packages/backend/test/unit/MfmService.ts
@@ -33,6 +33,12 @@ describe('MfmService', () => {
 			const output = '<p><span>foo<br>bar<br>baz</span></p>';
 			assert.equal(mfmService.toHtml(mfm.parse(input)), output);
 		});
+
+		test('Do not generate unnecessary span', () => {
+			const input = 'foo $[tada bar]';
+			const output = '<p>foo <i>bar</i></p>';
+			assert.equal(mfmService.toHtml(mfm.parse(input)), output);
+		});
 	});
 
 	describe('fromHtml', () => {