diff --git a/src/middleware/basic-auth/index.ts b/src/middleware/basic-auth/index.ts
index d23400d17..f1a2c3797 100644
--- a/src/middleware/basic-auth/index.ts
+++ b/src/middleware/basic-auth/index.ts
@@ -75,7 +75,7 @@ export const basicAuth = (
   }
 
   return async function basicAuth(ctx, next) {
-    const requestUser = auth(ctx.req)
+    const requestUser = auth(ctx.req.raw)
     if (requestUser) {
       if (verifyUserInOptions) {
         if (await options.verifyUser(requestUser.username, requestUser.password, ctx)) {
diff --git a/src/utils/basic-auth.test.ts b/src/utils/basic-auth.test.ts
index 1031eacf7..01e15dae7 100644
--- a/src/utils/basic-auth.test.ts
+++ b/src/utils/basic-auth.test.ts
@@ -3,61 +3,55 @@ import { auth } from './basic-auth'
 
 describe('auth', () => {
   it('auth() - not include Authorization Header', () => {
-    const req = new HonoRequest(new Request('http://localhost/auth'))
-    const res = auth(req)
+    const res = auth(new Request('http://localhost/auth'))
     expect(res).toBeUndefined()
   })
 
   it('auth() - invalid Authorization Header format', () => {
-    const req = new HonoRequest(
+    const res = auth(
       new Request('http://localhost/auth', {
         headers: { Authorization: 'InvalidAuthHeader' },
       })
     )
-    const res = auth(req)
     expect(res).toBeUndefined()
   })
 
   it('auth() - invalid Base64 string in Authorization Header', () => {
-    const req = new HonoRequest(
+    const res = auth(
       new Request('http://localhost/auth', {
         headers: { Authorization: 'Basic InvalidBase64' },
       })
     )
-    const res = auth(req)
     expect(res).toBeUndefined()
   })
 
   it('auth() - valid Authorization Header', () => {
     const validBase64 = btoa('username:password')
-    const req = new HonoRequest(
+    const res = auth(
       new Request('http://localhost/auth', {
         headers: { Authorization: `Basic ${validBase64}` },
       })
     )
-    const res = auth(req)
     expect(res).toEqual({ username: 'username', password: 'password' })
   })
 
   it('auth() - empty username', () => {
     const validBase64 = btoa(':password')
-    const req = new HonoRequest(
+    const res = auth(
       new Request('http://localhost/auth', {
         headers: { Authorization: `Basic ${validBase64}` },
       })
     )
-    const res = auth(req)
     expect(res).toEqual({ username: '', password: 'password' })
   })
 
   it('auth() - empty password', () => {
     const validBase64 = btoa('username:')
-    const req = new HonoRequest(
+    const res = auth(
       new Request('http://localhost/auth', {
         headers: { Authorization: `Basic ${validBase64}` },
       })
     )
-    const res = auth(req)
     expect(res).toEqual({ username: 'username', password: '' })
   })
 })
diff --git a/src/utils/basic-auth.ts b/src/utils/basic-auth.ts
index 37d895913..a2efa881f 100644
--- a/src/utils/basic-auth.ts
+++ b/src/utils/basic-auth.ts
@@ -1,14 +1,13 @@
-import type { HonoRequest } from '../request'
 import { decodeBase64 } from './encode'
 
 const CREDENTIALS_REGEXP = /^ *(?:[Bb][Aa][Ss][Ii][Cc]) +([A-Za-z0-9._~+/-]+=*) *$/
 const USER_PASS_REGEXP = /^([^:]*):(.*)$/
 const utf8Decoder = new TextDecoder()
 
-export type Auth = (req: HonoRequest) => { username: string; password: string } | undefined
+export type Auth = (req: Request) => { username: string; password: string } | undefined
 
-export const auth: Auth = (req: HonoRequest) => {
-  const match = CREDENTIALS_REGEXP.exec(req.header('Authorization') || '')
+export const auth: Auth = (req: Request) => {
+  const match = CREDENTIALS_REGEXP.exec(req.headers.get('Authorization') || '')
   if (!match) {
     return undefined
   }