diff --git a/packages/web/src/app/[lng]/(sub)/join/funnels/step1/components/NumberForm.tsx b/packages/web/src/app/[lng]/(sub)/join/funnels/step1/components/NumberForm.tsx
index ee35cea0d..bf6e75bd0 100644
--- a/packages/web/src/app/[lng]/(sub)/join/funnels/step1/components/NumberForm.tsx
+++ b/packages/web/src/app/[lng]/(sub)/join/funnels/step1/components/NumberForm.tsx
@@ -1,3 +1,4 @@
+import { useSearchParams } from 'next/navigation';
 import { ElementType, KeyboardEventHandler } from 'react';
 
 import { useJoinContext } from '../../../components/JoinContext';
@@ -15,6 +16,7 @@ import { Spacing } from '@/components/Spacing';
 import { TextFieldController } from '@/components/TextField';
 import { DEMO_ID } from '@/constants';
 import { regexr } from '@/constants/regexr';
+import { useDidMount } from '@/hooks/common/useDidMount';
 import useToast from '@/hooks/useModal/useToast';
 
 interface NumberSectionProps {
@@ -30,6 +32,13 @@ export default function NumberForm({ inputStatus, setInputStatus }: NumberSectio
   const { start: timerStart, status: timerStatus } = useTimerContext();
   const { openToast } = useToast();
   const { mutate: mutateLogin } = useLoginMutation();
+  const searchParams = useSearchParams();
+
+  useDidMount(() => {
+    if (searchParams.get('demo')) {
+      setValue('phoneNumber', '010-8969-5610', { shouldValidate: true });
+    }
+  });
 
   const handleInputChange = (
     e: React.ChangeEvent<HTMLInputElement> | React.KeyboardEvent<HTMLInputElement>
diff --git a/packages/web/src/constants/index.ts b/packages/web/src/constants/index.ts
index 9c22376eb..aeb040a20 100644
--- a/packages/web/src/constants/index.ts
+++ b/packages/web/src/constants/index.ts
@@ -7,4 +7,4 @@ export const DAY_OF_WEEK = ['SUN', 'MON', 'TUE', 'WED', 'THU', 'FRI', 'SAT'];
 export const GOOGLE_API_KEY = process.env.NEXT_PUBLIC_GOOGLE_MAP_API_KEY;
 export const SENTRY_DSN = process.env.NEXT_PUBLIC_SENTRY_DSN || '';
 export const GA_TRACKING_ID = process.env.NEXT_PUBLIC_GOOGLE_ID;
-export const DEMO_ID = process.env.NEXT_PUBLIC_DEMO_ID;
+export const DEMO_ID = process.env.NEXT_PUBLIC_DEMO_ID ?? '';