diff --git a/src/misc/reaction-lib.ts b/src/misc/reaction-lib.ts
index 20051f028..008991454 100644
--- a/src/misc/reaction-lib.ts
+++ b/src/misc/reaction-lib.ts
@@ -20,7 +20,7 @@ export async function getFallbackReaction(): Promise<string> {
 	return  meta.useStarForReactionFallback ? 'star' : 'like';
 }
 
-export async function toDbReaction(reaction: string, enableEmoji = true): Promise<string> {
+export async function toDbReaction(reaction?: string | null, enableEmoji = true): Promise<string> {
 	if (reaction == null) return await getFallbackReaction();
 
 	// 既存の文字列リアクションはそのまま
diff --git a/src/remote/activitypub/models/note.ts b/src/remote/activitypub/models/note.ts
index 9ed2fd641..c11a77b0f 100644
--- a/src/remote/activitypub/models/note.ts
+++ b/src/remote/activitypub/models/note.ts
@@ -152,7 +152,7 @@ export async function createNote(value: any, resolver?: Resolver, silent = false
 	const cw = note.summary === '' ? null : note.summary;
 
 	// テキストのパース
-	const text = note._misskey_content || fromHtml(note.content);
+	const text = note._misskey_content || (note.content ? fromHtml(note.content) : null);
 
 	// vote
 	if (reply && reply.hasPoll) {
diff --git a/src/remote/activitypub/type.ts b/src/remote/activitypub/type.ts
index 7e81a7cc4..95c69fb8a 100644
--- a/src/remote/activitypub/type.ts
+++ b/src/remote/activitypub/type.ts
@@ -12,7 +12,7 @@ export interface IObject {
 	attachment?: any[];
 	inReplyTo?: any;
 	replies?: ICollection;
-	content: string;
+	content?: string;
 	name?: string;
 	startTime?: Date;
 	endTime?: Date;
@@ -44,16 +44,16 @@ export interface IOrderedCollection extends IObject {
 
 export interface INote extends IObject {
 	type: 'Note' | 'Question';
-	_misskey_content: string;
-	_misskey_quote: string;
-	_misskey_question: string;
+	_misskey_content?: string;
+	_misskey_quote?: string;
+	_misskey_question?: string;
 }
 
 export interface IQuestion extends IObject {
 	type: 'Note' | 'Question';
-	_misskey_content: string;
-	_misskey_quote: string;
-	_misskey_question: string;
+	_misskey_content?: string;
+	_misskey_quote?: string;
+	_misskey_question?: string;
 	oneOf?: IQuestionChoice[];
 	anyOf?: IQuestionChoice[];
 	endTime?: Date;
@@ -129,7 +129,7 @@ export interface IRemove extends IActivity {
 
 export interface ILike extends IActivity {
 	type: 'Like';
-	_misskey_reaction: string;
+	_misskey_reaction?: string;
 }
 
 export interface IAnnounce extends IActivity {
diff --git a/src/services/note/reaction/create.ts b/src/services/note/reaction/create.ts
index ea2108430..6db210ea6 100644
--- a/src/services/note/reaction/create.ts
+++ b/src/services/note/reaction/create.ts
@@ -16,7 +16,7 @@ import { NoteReaction } from '../../../models/entities/note-reaction';
 import { createNotification } from '../../create-notification';
 import { isDuplicateKeyValueError } from '../../../misc/is-duplicate-key-value-error';
 
-export default async (user: User, note: Note, reaction: string) => {
+export default async (user: User, note: Note, reaction?: string) => {
 	// Myself
 	if (note.userId === user.id) {
 		throw new IdentifiableError('2d8e7297-1873-4c00-8404-792c68d7bef0', 'cannot react to my note');