diff --git a/VQCalendarAttention/Program.cs b/VQCalendarAttention/Program.cs
index 66c84eb..0c1bf10 100644
--- a/VQCalendarAttention/Program.cs
+++ b/VQCalendarAttention/Program.cs
@@ -32,7 +32,7 @@
                         //var cronExpression = CronExpression.Parse("* * * * *");
 
                         // タイムゾーンを東京に設定
-                        var timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById("Tokyo Standard Time");
+                        var timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById("Asia/Tokyo");
 
                         string calendarId = DotNetEnv.Env.GetString("CALENDAR_ID");
                         string CredentialsFilePath = DotNetEnv.Env.GetString("CREDENTIALS_FILE_PATH");
@@ -49,7 +49,7 @@
                         //var cronExpression = CronExpression.Parse("* * * * *");
 
                         // タイムゾーンを東京に設定
-                        var timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById("Tokyo Standard Time");
+                        var timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById("Asia/Tokyo");
 
                         string calendarId = DotNetEnv.Env.GetString("CALENDAR_ID");
                         string CredentialsFilePath = DotNetEnv.Env.GetString("CREDENTIALS_FILE_PATH");
diff --git a/VQCalendarAttention/Services/ImportantCalendarAttentionService.cs b/VQCalendarAttention/Services/ImportantCalendarAttentionService.cs
index a899909..917aee0 100644
--- a/VQCalendarAttention/Services/ImportantCalendarAttentionService.cs
+++ b/VQCalendarAttention/Services/ImportantCalendarAttentionService.cs
@@ -44,7 +44,7 @@
             CalendarService service = CalendarApiTest.getCalendarService(_credentialsFilePath);
 
             // タイムゾーンを指定してUTCからJSTへ変換
-            TimeZoneInfo tzi = TimeZoneInfo.FindSystemTimeZoneById("Tokyo Standard Time");
+            TimeZoneInfo tzi = TimeZoneInfo.FindSystemTimeZoneById("Asia/Tokyo");
             DateTime jst = TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, tzi);
 
             // イベントリストのリクエストを作成
diff --git a/VQCalendarAttention/Services/NextDayCalendarAttentionService.cs b/VQCalendarAttention/Services/NextDayCalendarAttentionService.cs
index c893df0..b26bf08 100644
--- a/VQCalendarAttention/Services/NextDayCalendarAttentionService.cs
+++ b/VQCalendarAttention/Services/NextDayCalendarAttentionService.cs
@@ -42,7 +42,7 @@
             CalendarService service = CalendarApiTest.getCalendarService(_credentialsFilePath);
             
             // タイムゾーンを指定してUTCからJSTへ変換
-            TimeZoneInfo tzi = TimeZoneInfo.FindSystemTimeZoneById("Tokyo Standard Time");
+            TimeZoneInfo tzi = TimeZoneInfo.FindSystemTimeZoneById("Asia/Tokyo");
             DateTime jst = TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, tzi);
 
             // イベントリストのリクエストを作成