diff --git a/package.json b/package.json
index e28a853..f3e572b 100644
--- a/package.json
+++ b/package.json
@@ -70,7 +70,7 @@
     "@types/supertest": "^2.0.12",
     "@whatwg-node/fetch": "^0.9.14",
     "eslint": "^8.55.0",
-    "hono": "^3.11.7",
+    "hono": "^3.12.8",
     "jest": "^29.6.1",
     "np": "^7.7.0",
     "prettier": "^3.2.4",
diff --git a/src/utils.ts b/src/utils.ts
index 97cac17..8117fbb 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -55,7 +55,7 @@ export const buildOutgoingHttpHeaders = (headers: Headers): OutgoingHttpHeaders
   if (cookies.length > 0) {
     res['set-cookie'] = cookies
   }
-  res['content-type'] ??= 'text/plain;charset=UTF-8'
+  res['content-type'] ??= 'text/plain; charset=UTF-8'
 
   return res
 }
diff --git a/test/server.test.ts b/test/server.test.ts
index 409f32e..d07cd95 100644
--- a/test/server.test.ts
+++ b/test/server.test.ts
@@ -39,7 +39,7 @@ describe('Basic', () => {
   it('Should return 200 response - GET /', async () => {
     const res = await request(server).get('/')
     expect(res.status).toBe(200)
-    expect(res.headers['content-type']).toMatch(/text\/plain/)
+    expect(res.headers['content-type']).toMatch('text/plain')
     expect(res.text).toBe('Hello! Node!')
   })
 
@@ -52,7 +52,7 @@ describe('Basic', () => {
   it('Should return 200 response - GET /user-agent', async () => {
     const res = await request(server).get('/user-agent').set('user-agent', 'Hono')
     expect(res.status).toBe(200)
-    expect(res.headers['content-type']).toMatch(/text\/plain/)
+    expect(res.headers['content-type']).toMatch('text/plain')
     expect(res.text).toBe('Hono')
   })
 
@@ -71,13 +71,13 @@ describe('Basic', () => {
   it('Should return 500 response - GET /invalid', async () => {
     const res = await request(server).get('/invalid')
     expect(res.status).toBe(500)
-    expect(res.headers['content-type']).toBe('text/plain')
+    expect(res.headers['content-type']).toEqual('text/plain')
   })
 
   it('Should return 200 response - GET /ponyfill', async () => {
     const res = await request(server).get('/ponyfill')
     expect(res.status).toBe(200)
-    expect(res.headers['content-type']).toMatch(/text\/plain/)
+    expect(res.headers['content-type']).toMatch('text/plain')
     expect(res.text).toBe('Pony')
   })
 })
@@ -189,28 +189,28 @@ describe('Response body', () => {
     it('Should return JSON body', async () => {
       const res = await request(server).get('/json')
       expect(res.status).toBe(200)
-      expect(res.headers['content-type']).toMatch(/application\/json/)
+      expect(res.headers['content-type']).toMatch('application/json')
       expect(JSON.parse(res.text)).toEqual({ foo: 'bar' })
     })
 
     it('Should return JSON body from /json-async', async () => {
       const res = await request(server).get('/json-async')
       expect(res.status).toBe(200)
-      expect(res.headers['content-type']).toMatch(/application\/json/)
+      expect(res.headers['content-type']).toMatch('application/json')
       expect(JSON.parse(res.text)).toEqual({ foo: 'async' })
     })
 
     it('Should return HTML', async () => {
       const res = await request(server).get('/html')
       expect(res.status).toBe(200)
-      expect(res.headers['content-type']).toMatch(/text\/html/)
+      expect(res.headers['content-type']).toMatch('text/html')
       expect(res.text).toBe('<h1>Hello!</h1>')
     })
 
     it('Should return HTML from /html-async', async () => {
       const res = await request(server).get('/html-async')
       expect(res.status).toBe(200)
-      expect(res.headers['content-type']).toMatch(/text\/html/)
+      expect(res.headers['content-type']).toMatch('text/html')
       expect(res.text).toBe('<h1>Hello!</h1>')
     })
   })
@@ -235,14 +235,14 @@ describe('Response body', () => {
     it('Should return JSON body from /json-blob', async () => {
       const res = await request(server).get('/json-blob')
       expect(res.status).toBe(200)
-      expect(res.headers['content-type']).toMatch(/application\/json/)
+      expect(res.headers['content-type']).toMatch('application/json')
       expect(JSON.parse(res.text)).toEqual({ foo: 'blob' })
     })
 
     it('Should return JSON body from /json-buffer', async () => {
       const res = await request(server).get('/json-buffer')
       expect(res.status).toBe(200)
-      expect(res.headers['content-type']).toMatch(/application\/json/)
+      expect(res.headers['content-type']).toMatch('application/json')
       expect(JSON.parse(res.text)).toEqual({ foo: 'buffer' })
     })
   })
@@ -394,7 +394,7 @@ describe('Stream and non-stream response', () => {
     const res = await request(server).get('/json')
     expect(res.status).toBe(200)
     expect(res.headers['content-length']).toMatch('13')
-    expect(res.headers['content-type']).toMatch(/application\/json/)
+    expect(res.headers['content-type']).toMatch('application/json')
     expect(JSON.parse(res.text)).toEqual({ foo: 'bar' })
   })
 
@@ -402,7 +402,7 @@ describe('Stream and non-stream response', () => {
     const res = await request(server).get('/text')
     expect(res.status).toBe(200)
     expect(res.headers['content-length']).toMatch('6')
-    expect(res.headers['content-type']).toMatch(/text\/plain/)
+    expect(res.headers['content-type']).toMatch('text/plain')
     expect(res.text).toBe('Hello!')
   })
 
@@ -410,8 +410,8 @@ describe('Stream and non-stream response', () => {
     const res = await request(server).get('/json-stream')
     expect(res.status).toBe(200)
     expect(res.headers['content-length']).toBeUndefined()
-    expect(res.headers['content-type']).toMatch(/application\/json/)
-    expect(res.headers['transfer-encoding']).toMatch(/chunked/)
+    expect(res.headers['content-type']).toMatch('application/json')
+    expect(res.headers['transfer-encoding']).toMatch('chunked')
     expect(JSON.parse(res.text)).toEqual({ foo: 'bar' })
   })
 
@@ -429,8 +429,8 @@ describe('Stream and non-stream response', () => {
       })
     expect(res.status).toBe(200)
     expect(res.headers['content-length']).toBeUndefined()
-    expect(res.headers['content-type']).toMatch(/text\/event-stream/)
-    expect(res.headers['transfer-encoding']).toMatch(/chunked/)
+    expect(res.headers['content-type']).toMatch('text/event-stream')
+    expect(res.headers['transfer-encoding']).toMatch('chunked')
   })
 
   it('Should return error - stream without app crashing', async () => {
@@ -455,7 +455,7 @@ describe('SSL', () => {
   it('Should return 200 response - GET /', async () => {
     const res = await request(server).get('/').trustLocalhost()
     expect(res.status).toBe(200)
-    expect(res.headers['content-type']).toMatch(/text\/plain/)
+    expect(res.headers['content-type']).toMatch('text/plain')
     expect(res.text).toBe('Hello! Node!')
   })
 })
@@ -479,7 +479,7 @@ describe('HTTP2', () => {
     // @ts-expect-error: @types/supertest is not updated yet
     const res = await request(server, { http2: true }).get('/').trustLocalhost()
     expect(res.status).toBe(200)
-    expect(res.headers['content-type']).toMatch(/text\/plain/)
+    expect(res.headers['content-type']).toMatch('text/plain')
     expect(res.text).toBe('Hello! Node!')
   })
 
@@ -487,7 +487,7 @@ describe('HTTP2', () => {
     // @ts-expect-error: @types/supertest is not updated yet
     const res = await request(server, { http2: true }).get('/headers').trustLocalhost()
     expect(res.status).toBe(200)
-    expect(res.headers['content-type']).toMatch(/text\/plain/)
+    expect(res.headers['content-type']).toMatch('text/plain')
     expect(res.text).toBe('Hello! Node!')
   })
 
@@ -496,15 +496,27 @@ describe('HTTP2', () => {
     // @ts-expect-error: @types/supertest is not updated yet
     const res = await request(server, { http2: true }).get('/url').trustLocalhost()
     expect(res.status).toBe(200)
-    expect(res.headers['content-type']).toMatch(/text\/plain/)
+    expect(res.headers['content-type']).toMatch('text/plain')
     expect(new URL(res.text).hostname).toBe('127.0.0.1')
   })
 })
 
-describe('Hono compression', () => {
+describe('Hono compression default gzip', () => {
   const app = new Hono()
   app.use('*', compress())
 
+  app.notFound((c) => {
+    return c.text('Custom NotFound', 404)
+  })
+
+  app.onError((_, c) => {
+    return c.text('Custom Error!', 500)
+  })
+
+  app.get('/error', () => {
+    throw new Error()
+  })
+
   app.get('/one', async (c) => {
     let body = 'one'
 
@@ -514,12 +526,82 @@ describe('Hono compression', () => {
     return c.text(body)
   })
 
-  it('Should return 200 response - GET /one', async () => {
+  it('should return 200 response - GET /one', async () => {
     const server = createAdaptorServer(app)
     const res = await request(server).get('/one')
     expect(res.status).toBe(200)
-    expect(res.headers['content-type']).toMatch(/text\/plain/)
-    expect(res.headers['content-encoding']).toMatch(/gzip/)
+    expect(res.headers['content-type']).toMatch('text/plain')
+    expect(res.headers['content-encoding']).toMatch('gzip')
+  })
+
+  it('should return 404 Custom NotFound', async () => {
+    const server = createAdaptorServer(app)
+    const res = await request(server).get('/err')
+    expect(res.status).toBe(404)
+    expect(res.text).toEqual('Custom NotFound')
+    expect(res.headers['content-type']).toEqual('text/plain; charset=UTF-8')
+    expect(res.headers['content-encoding']).toMatch('gzip')
+  })
+
+  it('should return 500 Custom Error!', async () => {
+    const server = createAdaptorServer(app)
+    const res = await request(server).get('/error')
+    expect(res.status).toBe(500)
+    expect(res.text).toEqual('Custom Error!')
+    expect(res.headers['content-type']).toEqual('text/plain; charset=UTF-8')
+    expect(res.headers['content-encoding']).toMatch('gzip')
+  })
+})
+
+describe('Hono compression deflate', () => {
+  const app = new Hono()
+  app.use('*', compress({ encoding: 'deflate' }))
+
+  app.notFound((c) => {
+    return c.text('Custom NotFound', 404)
+  })
+
+  app.onError((_, c) => {
+    return c.text('Custom Error!', 500)
+  })
+
+  app.get('/error', () => {
+    throw new Error()
+  })
+
+  app.get('/one', async (c) => {
+    let body = 'one'
+
+    for (let index = 0; index < 1000 * 1000; index++) {
+      body += ' one'
+    }
+    return c.text(body)
+  })
+
+  it('should return 200 response - GET /one', async () => {
+    const server = createAdaptorServer(app)
+    const res = await request(server).get('/one')
+    expect(res.status).toBe(200)
+    expect(res.headers['content-type']).toMatch('text/plain')
+    expect(res.headers['content-encoding']).toMatch('deflate')
+  })
+
+  it('should return 404 Custom NotFound', async () => {
+    const server = createAdaptorServer(app)
+    const res = await request(server).get('/err')
+    expect(res.status).toBe(404)
+    expect(res.text).toEqual('Custom NotFound')
+    expect(res.headers['content-type']).toEqual('text/plain; charset=UTF-8')
+    expect(res.headers['content-encoding']).toMatch('deflate')
+  })
+
+  it('should return 500 Custom Error!', async () => {
+    const server = createAdaptorServer(app)
+    const res = await request(server).get('/error')
+    expect(res.status).toBe(500)
+    expect(res.text).toEqual('Custom Error!')
+    expect(res.headers['content-type']).toEqual('text/plain; charset=UTF-8')
+    expect(res.headers['content-encoding']).toMatch('deflate')
   })
 })
 
@@ -539,7 +621,7 @@ describe('set child response to c.res', () => {
     const server = createAdaptorServer(app)
     const res = await request(server).get('/json')
     expect(res.status).toBe(200)
-    expect(res.headers['content-type']).toMatch(/application\/json/)
+    expect(res.headers['content-type']).toMatch('application/json')
   })
 })
 
diff --git a/yarn.lock b/yarn.lock
index 6b5b8eb..1e2609a 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2924,10 +2924,10 @@ hexoid@^1.0.0:
   resolved "https://registry.yarnpkg.com/hexoid/-/hexoid-1.0.0.tgz#ad10c6573fb907de23d9ec63a711267d9dc9bc18"
   integrity sha512-QFLV0taWQOZtvIRIAdBChesmogZrtuXvVWsFHZTk2SU+anspqZ2vMnoLg7IE1+Uk16N19APic1BuF8bC8c2m5g==
 
-hono@^3.11.7:
-  version "3.11.7"
-  resolved "https://registry.yarnpkg.com/hono/-/hono-3.11.7.tgz#e44f8aa3a18f19775304328bde6f559f7a02447f"
-  integrity sha512-TcfAq7IdipF+9coxnuzYlSSBXbm9mTyWjjagLCv/2ampboNcKJdi+XCK5G48mHQtpI5+9Rj3J4FfcGgw9vzIww==
+hono@^3.12.8:
+  version "3.12.8"
+  resolved "https://registry.yarnpkg.com/hono/-/hono-3.12.8.tgz#7c137aa6ac7bcd2aec3f55b9596d71e97081963a"
+  integrity sha512-vnOEIRdqsp4uHE/dkOBr9EYmTsR86sD/FyG2xhfAQzR9udDRglN1nuO7SGc/7U3HfSorc6PSCNGN6upnVtCmfg==
 
 hosted-git-info@^2.1.4:
   version "2.8.9"