diff --git a/packages/backend/src/misc/populate-emojis.ts b/packages/backend/src/misc/populate-emojis.ts
index 9e788d8be..26c05e5fa 100644
--- a/packages/backend/src/misc/populate-emojis.ts
+++ b/packages/backend/src/misc/populate-emojis.ts
@@ -62,7 +62,8 @@ export async function populateEmoji(emojiName: string, noteUserHost: string | nu
 	if (emoji == null) return null;
 
 	const isLocal = emoji.host == null;
-	const url = isLocal ? emoji.publicUrl : `${config.url}/proxy/image.png?${query({ url: emoji.publicUrl })}`;
+	const emojiUrl = emoji.publicUrl || emoji.originalUrl; // || emoji.originalUrl してるのは後方互換性のため
+	const url = isLocal ? emojiUrl : `${config.url}/proxy/image.png?${query({ url: emojiUrl })}`;
 
 	return {
 		name: emojiName,
diff --git a/packages/backend/src/remote/activitypub/renderer/emoji.ts b/packages/backend/src/remote/activitypub/renderer/emoji.ts
index 0c0bc382f..e7ae7d959 100644
--- a/packages/backend/src/remote/activitypub/renderer/emoji.ts
+++ b/packages/backend/src/remote/activitypub/renderer/emoji.ts
@@ -9,6 +9,6 @@ export default (emoji: Emoji) => ({
 	icon: {
 		type: 'Image',
 		mediaType: emoji.type || 'image/png',
-		url: emoji.publicUrl,
+		url: emoji.publicUrl || emoji.originalUrl, // || emoji.originalUrl してるのは後方互換性のため
 	},
 });
diff --git a/packages/backend/src/services/note/reaction/create.ts b/packages/backend/src/services/note/reaction/create.ts
index 795bb691c..47f46419d 100644
--- a/packages/backend/src/services/note/reaction/create.ts
+++ b/packages/backend/src/services/note/reaction/create.ts
@@ -88,7 +88,7 @@ export default async (user: { id: User['id']; host: User['host']; }, note: Note,
 		reaction: decodedReaction.reaction,
 		emoji: emoji != null ? {
 			name: emoji.host ? `${emoji.name}@${emoji.host}` : `${emoji.name}@.`,
-			url: emoji.publicUrl ?? emoji.originalUrl,
+			url: emoji.publicUrl || emoji.originalUrl, // || emoji.originalUrl してるのは後方互換性のため
 		} : null,
 		userId: user.id,
 	});