diff --git a/src/models/messaging-history.ts b/src/models/messaging-history.ts
index 6864e22d2f..5367f81412 100644
--- a/src/models/messaging-history.ts
+++ b/src/models/messaging-history.ts
@@ -11,3 +11,30 @@ export type IMessagingHistory = {
 	partnerId: mongo.ObjectID;
 	messageId: mongo.ObjectID;
 };
+
+/**
+ * MessagingHistoryを物理削除します
+ */
+export async function deleteMessagingHistory(messagingHistory: string | mongo.ObjectID | IMessagingHistory) {
+	let m: IMessagingHistory;
+
+	// Populate
+	if (mongo.ObjectID.prototype.isPrototypeOf(messagingHistory)) {
+		m = await MessagingHistory.findOne({
+			_id: messagingHistory
+		});
+	} else if (typeof messagingHistory === 'string') {
+		m = await MessagingHistory.findOne({
+			_id: new mongo.ObjectID(messagingHistory)
+		});
+	} else {
+		m = messagingHistory as IMessagingHistory;
+	}
+
+	if (m == null) return;
+
+	// このMessagingHistoryを削除
+	await MessagingHistory.remove({
+		_id: m._id
+	});
+}
diff --git a/src/models/messaging-message.ts b/src/models/messaging-message.ts
index 974ee54ab8..9d62fab4fa 100644
--- a/src/models/messaging-message.ts
+++ b/src/models/messaging-message.ts
@@ -3,6 +3,7 @@ import deepcopy = require('deepcopy');
 import { pack as packUser } from './user';
 import { pack as packFile } from './drive-file';
 import db from '../db/mongodb';
+import MessagingHistory, { deleteMessagingHistory } from './messaging-history';
 
 const MessagingMessage = db.get<IMessagingMessage>('messagingMessages');
 export default MessagingMessage;
@@ -22,13 +23,40 @@ export function isValidText(text: string): boolean {
 	return text.length <= 1000 && text.trim() != '';
 }
 
+/**
+ * MessagingMessageを物理削除します
+ */
+export async function deleteMessagingMessage(messagingMessage: string | mongo.ObjectID | IMessagingMessage) {
+	let m: IMessagingMessage;
+
+	// Populate
+	if (mongo.ObjectID.prototype.isPrototypeOf(messagingMessage)) {
+		m = await MessagingMessage.findOne({
+			_id: messagingMessage
+		});
+	} else if (typeof messagingMessage === 'string') {
+		m = await MessagingMessage.findOne({
+			_id: new mongo.ObjectID(messagingMessage)
+		});
+	} else {
+		m = messagingMessage as IMessagingMessage;
+	}
+
+	if (m == null) return;
+
+	// このMessagingMessageを指すMessagingHistoryをすべて削除
+	await Promise.all((
+		await MessagingHistory.find({ messageId: m._id })
+	).map(x => deleteMessagingHistory(x)));
+
+	// このMessagingMessageを削除
+	await MessagingMessage.remove({
+		_id: m._id
+	});
+}
+
 /**
  * Pack a messaging message for API response
- *
- * @param {any} message
- * @param {any} me?
- * @param {any} options?
- * @return {Promise<any>}
  */
 export const pack = (
 	message: any,
diff --git a/src/models/user.ts b/src/models/user.ts
index b1a68b0827..6155324be8 100644
--- a/src/models/user.ts
+++ b/src/models/user.ts
@@ -11,6 +11,8 @@ import AccessToken, { deleteAccessToken } from './access-token';
 import NoteWatching, { deleteNoteWatching } from './note-watching';
 import Favorite, { deleteFavorite } from './favorite';
 import NoteReaction, { deleteNoteReaction } from './note-reaction';
+import MessagingMessage, { deleteMessagingMessage } from './messaging-message';
+import MessagingHistory, { deleteMessagingHistory } from './messaging-history';
 
 const User = db.get<IUser>('users');
 
@@ -173,8 +175,19 @@ export async function deleteUser(user: string | mongo.ObjectID | IUser) {
 	).map(x => deleteFavorite(x)));
 
 	// このユーザーのMessageをすべて削除
+	await Promise.all((
+		await MessagingMessage.find({ userId: u._id })
+	).map(x => deleteMessagingMessage(x)));
 
 	// このユーザーへのMessageをすべて削除
+	await Promise.all((
+		await MessagingMessage.find({ recipientId: u._id })
+	).map(x => deleteMessagingMessage(x)));
+
+	// このユーザーの関わるMessagingHistoryをすべて削除
+	await Promise.all((
+		await MessagingHistory.find({ $or: [{ partnerId: u._id }, { userId: u._id }] })
+	).map(x => deleteMessagingHistory(x)));
 
 	// このユーザーのDriveFileをすべて削除