diff --git a/function.php b/function.php
index 1133c01d..39d52582 100644
--- a/function.php
+++ b/function.php
@@ -17,7 +17,6 @@ use Kiri\Exception\ConfigException;
 use Kiri\Exception\NotFindClassException;
 use Kiri\Kiri;
 use Psr\Log\LoggerInterface;
-use Server\ServerManager;
 use Swoole\Process;
 use Swoole\WebSocket\Server;
 
@@ -157,7 +156,9 @@ if (!function_exists('now')) {
 	 */
 	function now(): string
 	{
-		return date('Y-m-d H:i:s') . '.' . str_replace(time() . '.', '', (string)microtime(true));
+		$sprintf = sprintf('%04d', microtime(true));
+
+		return date('Y-m-d H:i:s') . '.' . str_replace(time() . '.', '', $sprintf);
 	}
 }