diff --git a/common.php b/common.php
index f44cb91..819022a 100644
--- a/common.php
+++ b/common.php
@@ -1,6 +1,8 @@
-<?php
+<?php
 declare(strict_types=1);
 
+date_default_timezone_set('Asia/Seoul');
+
 $carSecretFile = '/home/seo/secret/car.php';
 if (!is_file($carSecretFile)) {
     throw new RuntimeException('Missing car secret config: ' . $carSecretFile);
diff --git a/monitor.php b/monitor.php
index f87424e..49defe8 100644
--- a/monitor.php
+++ b/monitor.php
@@ -1,6 +1,8 @@
 <?php
 declare(strict_types=1);
 
+date_default_timezone_set('Asia/Seoul');
+
 $carSecretFile = '/home/seo/secret/car.php';
 if (!is_file($carSecretFile)) {
     throw new RuntimeException('Missing car secret config: ' . $carSecretFile);