diff --git a/booking-app/app.development.yaml b/booking-app/app.development.yaml
index 7e4ead83..c7e6f3a8 100644
--- a/booking-app/app.development.yaml
+++ b/booking-app/app.development.yaml
@@ -10,6 +10,7 @@ automatic_scaling:
 env_variables:
   NEXT_PUBLIC_BRANCH_NAME: "development"
   NODE_OPTIONS: "--max-old-space-size=4096"
+  TZ: "America/New_York"
 
 build_env_variables:
   NODE_OPTIONS: "--max-old-space-size=4096"
diff --git a/booking-app/app.production.yaml b/booking-app/app.production.yaml
index f40d61e2..2640c099 100644
--- a/booking-app/app.production.yaml
+++ b/booking-app/app.production.yaml
@@ -10,6 +10,7 @@ automatic_scaling:
 env_variables:
   NEXT_PUBLIC_BRANCH_NAME: "production"
   NODE_OPTIONS: "--max-old-space-size=4096"
+  TZ: "America/New_York"
 
 build_env_variables:
   NODE_OPTIONS: "--max-old-space-size=4096"
diff --git a/booking-app/app.staging.yaml b/booking-app/app.staging.yaml
index 6f890331..f53bfbb7 100644
--- a/booking-app/app.staging.yaml
+++ b/booking-app/app.staging.yaml
@@ -10,6 +10,7 @@ automatic_scaling:
 env_variables:
   NEXT_PUBLIC_BRANCH_NAME: "staging"
   NODE_OPTIONS: "--max-old-space-size=4096"
+  TZ: "America/New_York"
 
 build_env_variables:
   NODE_OPTIONS: "--max-old-space-size=4096"
diff --git a/booking-app/app/api/bookings/route.ts b/booking-app/app/api/bookings/route.ts
index 371755f6..468ccb85 100644
--- a/booking-app/app/api/bookings/route.ts
+++ b/booking-app/app/api/bookings/route.ts
@@ -161,13 +161,11 @@ export async function POST(request: NextRequest) {
     equipmentCheckedOut: false,
     ...data,
   });
-  console.log(" Done serverSaveDataToFirestore booking");
   await serverSaveDataToFirestore(TableNames.BOOKING_STATUS, {
     calendarEventId,
     email,
     requestedAt: Timestamp.now(),
   });
-  console.log(" Done serverSaveDataToFirestore booking status");
 
   await handleBookingApprovalEmails(
     isAutoApproval,
diff --git a/booking-app/components/src/client/utils/serverDate.ts b/booking-app/components/src/client/utils/serverDate.ts
index 050515a8..c4651a57 100644
--- a/booking-app/components/src/client/utils/serverDate.ts
+++ b/booking-app/components/src/client/utils/serverDate.ts
@@ -1,5 +1,7 @@
 import { Timestamp } from "firebase-admin/firestore";
-import { format } from "date-fns";
+import { toZonedTime } from "date-fns-tz";
+import { parseISO } from "date-fns";
+import { format } from "date-fns-tz";
 
 type DateInput = Date | Timestamp | { [key: string]: any } | number | string;
 
@@ -15,15 +17,26 @@ const parseTimestamp = (value: DateInput): Timestamp => {
 };
 
 export const serverFormatDate = (
-  input: DateInput,
+  input: string,
   timeZone: string = "America/New_York"
 ): string => {
   if (!input) return "";
   try {
-    const timestamp = parseTimestamp(input);
-    const date = timestamp.toDate();
-    const zonedDate = new Date(date.toLocaleString("en-US", { timeZone }));
-    return format(zonedDate, "yyyy-MM-dd hh:mm a");
+    const date = new Date(input);
+
+    const zonedDate = toZonedTime(date, timeZone);
+
+    const formattedResult = format(zonedDate, "yyyy-MM-dd hh:mm a", {
+      timeZone,
+    });
+
+    console.log("Input:", input);
+    console.log("Parsed Date:", date.toISOString());
+    console.log("Zoned Date:", zonedDate.toString());
+    console.log("Formatted Result:", formattedResult);
+    console.log("Timezone:", timeZone);
+
+    return formattedResult;
   } catch (error) {
     console.error("Error formatting date:", error, "Input:", input);
     return "";
diff --git a/booking-app/lib/googleClient.ts b/booking-app/lib/googleClient.ts
index 80a3be08..2da94dcd 100644
--- a/booking-app/lib/googleClient.ts
+++ b/booking-app/lib/googleClient.ts
@@ -14,9 +14,6 @@ const refreshAccessTokenIfNeeded = async (oauth2Client) => {
   const currentTime = Date.now();
   const tokenExpiryTime = oauth2Client.credentials.expiry_date;
 
-  console.log("Current time:", new Date(currentTime));
-  console.log("Token expiry:", new Date(tokenExpiryTime));
-
   if (!tokenExpiryTime || currentTime >= tokenExpiryTime - 60000) {
     // 1分前に更新
     try {
diff --git a/booking-app/package-lock.json b/booking-app/package-lock.json
index c9b33bc4..752525e8 100644
--- a/booking-app/package-lock.json
+++ b/booking-app/package-lock.json
@@ -24,6 +24,7 @@
         "axios": "^1.7.2",
         "bootstrap": "^5.3.3",
         "date-fns": "^3.6.0",
+        "date-fns-tz": "^3.1.3",
         "dayjs": "^1.11.12",
         "firebase": "^10.12.4",
         "firebase-admin": "^12.2.0",
@@ -5527,6 +5528,14 @@
         "url": "https://github.com/sponsors/kossnocorp"
       }
     },
+    "node_modules/date-fns-tz": {
+      "version": "3.1.3",
+      "resolved": "https://registry.npmjs.org/date-fns-tz/-/date-fns-tz-3.1.3.tgz",
+      "integrity": "sha512-ZfbMu+nbzW0mEzC8VZrLiSWvUIaI3aRHeq33mTe7Y38UctKukgqPR4nTDwcwS4d64Gf8GghnVsroBuMY3eiTeA==",
+      "peerDependencies": {
+        "date-fns": "^3.0.0"
+      }
+    },
     "node_modules/dayjs": {
       "version": "1.11.12",
       "resolved": "https://registry.npmjs.org/dayjs/-/dayjs-1.11.12.tgz",
diff --git a/booking-app/package.json b/booking-app/package.json
index 2dd39195..ba14c6ac 100644
--- a/booking-app/package.json
+++ b/booking-app/package.json
@@ -27,6 +27,7 @@
     "axios": "^1.7.2",
     "bootstrap": "^5.3.3",
     "date-fns": "^3.6.0",
+    "date-fns-tz": "^3.1.3",
     "dayjs": "^1.11.12",
     "firebase": "^10.12.4",
     "firebase-admin": "^12.2.0",