diff --git a/packages/backend/src/core/MfmService.ts b/packages/backend/src/core/MfmService.ts
index 9d175119d..74536c68f 100644
--- a/packages/backend/src/core/MfmService.ts
+++ b/packages/backend/src/core/MfmService.ts
@@ -7,16 +7,18 @@ import { URL } from 'node:url';
 import { Inject, Injectable } from '@nestjs/common';
 import * as parse5 from 'parse5';
 import { Window, XMLSerializer } from 'happy-dom';
-import * as TreeAdapter from 'parse5/dist/tree-adapters/default.js';
 import { DI } from '@/di-symbols.js';
 import type { Config } from '@/config.js';
 import { intersperse } from '@/misc/prelude/array.js';
 import { normalizeForSearch } from '@/misc/normalize-for-search.js';
 import type { IMentionedRemoteUsers } from '@/models/Note.js';
 import { bindThis } from '@/decorators.js';
+import type { DefaultTreeAdapterMap } from 'parse5';
 import type * as mfm from 'mfm-js';
 
-const treeAdapter = TreeAdapter.defaultTreeAdapter;
+const treeAdapter = parse5.defaultTreeAdapter;
+type Node = DefaultTreeAdapterMap['node'];
+type ChildNode = DefaultTreeAdapterMap['childNode'];
 
 const urlRegex = /^https?:\/\/[\w\/:%#@$&?!()\[\]~.,=+\-]+/;
 const urlRegexFull = /^https?:\/\/[\w\/:%#@$&?!()\[\]~.,=+\-]+$/;
@@ -46,7 +48,7 @@ export class MfmService {
 
 		return text.trim();
 
-		function getText(node: TreeAdapter.Node): string {
+		function getText(node: Node): string {
 			if (treeAdapter.isTextNode(node)) return node.value;
 			if (!treeAdapter.isElementNode(node)) return '';
 			if (node.nodeName === 'br') return '\n';
@@ -58,7 +60,7 @@ export class MfmService {
 			return '';
 		}
 
-		function appendChildren(childNodes: TreeAdapter.ChildNode[]): void {
+		function appendChildren(childNodes: ChildNode[]): void {
 			if (childNodes) {
 				for (const n of childNodes) {
 					analyze(n);
@@ -66,14 +68,16 @@ export class MfmService {
 			}
 		}
 
-		function analyze(node: TreeAdapter.Node) {
+		function analyze(node: Node) {
 			if (treeAdapter.isTextNode(node)) {
 				text += node.value;
 				return;
 			}
 
 			// Skip comment or document type node
-			if (!treeAdapter.isElementNode(node)) return;
+			if (!treeAdapter.isElementNode(node)) {
+				return;
+			}
 
 			switch (node.nodeName) {
 				case 'br': {
@@ -81,8 +85,7 @@ export class MfmService {
 					break;
 				}
 
-				case 'a':
-				{
+				case 'a': {
 					const txt = getText(node);
 					const rel = node.attrs.find(x => x.name === 'rel');
 					const href = node.attrs.find(x => x.name === 'href');
@@ -90,7 +93,7 @@ export class MfmService {
 					// ハッシュタグ
 					if (normalizedHashtagNames && href && normalizedHashtagNames.has(normalizeForSearch(txt))) {
 						text += txt;
-					// メンション
+						// メンション
 					} else if (txt.startsWith('@') && !(rel && rel.value.startsWith('me '))) {
 						const part = txt.split('@');
 
@@ -102,7 +105,7 @@ export class MfmService {
 						} else if (part.length === 3) {
 							text += txt;
 						}
-					// その他
+						// その他
 					} else {
 						const generateLink = () => {
 							if (!href && !txt) {
@@ -130,8 +133,7 @@ export class MfmService {
 					break;
 				}
 
-				case 'h1':
-				{
+				case 'h1': {
 					text += '【';
 					appendChildren(node.childNodes);
 					text += '】\n';
@@ -139,16 +141,14 @@ export class MfmService {
 				}
 
 				case 'b':
-				case 'strong':
-				{
+				case 'strong': {
 					text += '**';
 					appendChildren(node.childNodes);
 					text += '**';
 					break;
 				}
 
-				case 'small':
-				{
+				case 'small': {
 					text += '<small>';
 					appendChildren(node.childNodes);
 					text += '</small>';
@@ -156,8 +156,7 @@ export class MfmService {
 				}
 
 				case 's':
-				case 'del':
-				{
+				case 'del': {
 					text += '~~';
 					appendChildren(node.childNodes);
 					text += '~~';
@@ -165,8 +164,7 @@ export class MfmService {
 				}
 
 				case 'i':
-				case 'em':
-				{
+				case 'em': {
 					text += '<i>';
 					appendChildren(node.childNodes);
 					text += '</i>';
@@ -207,8 +205,7 @@ export class MfmService {
 				case 'h3':
 				case 'h4':
 				case 'h5':
-				case 'h6':
-				{
+				case 'h6': {
 					text += '\n\n';
 					appendChildren(node.childNodes);
 					break;
@@ -221,8 +218,7 @@ export class MfmService {
 				case 'article':
 				case 'li':
 				case 'dt':
-				case 'dd':
-				{
+				case 'dd': {
 					text += '\n';
 					appendChildren(node.childNodes);
 					break;