diff --git a/packages/backend/src/config.ts b/packages/backend/src/config.ts
index 65e58a560..bcf3e8f68 100644
--- a/packages/backend/src/config.ts
+++ b/packages/backend/src/config.ts
@@ -127,6 +127,8 @@ type Source = {
 	perUserNotificationsMaxCount?: number;
 	deactivateAntennaThreshold?: number;
 	pidFile: string;
+
+	extraHead?: string;
 };
 
 export type Config = {
@@ -232,6 +234,7 @@ export type Config = {
 	perUserNotificationsMaxCount: number;
 	deactivateAntennaThreshold: number;
 	pidFile: string;
+	extraHead: string | undefined;
 };
 
 const _filename = fileURLToPath(import.meta.url);
@@ -341,6 +344,7 @@ export function loadConfig(): Config {
 		perUserNotificationsMaxCount: config.perUserNotificationsMaxCount ?? 500,
 		deactivateAntennaThreshold: config.deactivateAntennaThreshold ?? (1000 * 60 * 60 * 24 * 7),
 		pidFile: config.pidFile,
+		extraHead: config.extraHead,
 	};
 }
 
diff --git a/packages/backend/src/server/web/ClientServerService.ts b/packages/backend/src/server/web/ClientServerService.ts
index 4aeb74de7..0173e7928 100644
--- a/packages/backend/src/server/web/ClientServerService.ts
+++ b/packages/backend/src/server/web/ClientServerService.ts
@@ -197,6 +197,7 @@ export class ClientServerService {
 			instanceUrl: this.config.url,
 			metaJson: htmlSafeJsonStringify(await this.metaEntityService.packDetailed(meta)),
 			now: Date.now(),
+			extraHead: this.config.extraHead,
 		};
 	}
 
diff --git a/packages/backend/src/server/web/views/base.pug b/packages/backend/src/server/web/views/base.pug
index ab3d0d957..40b567169 100644
--- a/packages/backend/src/server/web/views/base.pug
+++ b/packages/backend/src/server/web/views/base.pug
@@ -73,6 +73,8 @@ html
 
 		script(src=`/assets/boot.${version}.js`)
 
+		| !{extraHead}
+
 	body
 		noscript: p
 			| JavaScriptを有効にしてください