diff --git a/.github/workflows/ci-unknwnutil-validator.yml b/.github/workflows/ci-unknwnutil-validator.yml
new file mode 100644
index 00000000..42ee0359
--- /dev/null
+++ b/.github/workflows/ci-unknwnutil-validator.yml
@@ -0,0 +1,25 @@
+name: ci-unknownutil-validator
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'packages/unknownutil-validator/**'
+  pull_request:
+    branches: ['*']
+    paths:
+      - 'packages/unknownutil-validator/**'
+
+jobs:
+  ci:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: ./packages/unknownutil-validator
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: 18.x
+      - run: yarn install --frozen-lockfile
+      - run: yarn build
+      - run: yarn test
diff --git a/package.json b/package.json
index d209c801..1d61365d 100644
--- a/package.json
+++ b/package.json
@@ -18,6 +18,7 @@
     "build:typebox-validator": "yarn workspace @hono/typebox-validator build",
     "build:medley-router": "yarn workspace @hono/medley-router build",
     "build:valibot-validator": "yarn workspace @hono/valibot-validator build",
+    "build:unknownutil-validator": "yarn workspace @hono/unknownutil-validator build",
     "build:zod-openapi": "yarn build:zod-validator && yarn workspace @hono/zod-openapi build",
     "build:typia-validator": "yarn workspace @hono/typia-validator build",
     "build": "run-p build:*"
diff --git a/packages/unknownutil-validator/CHANGELOG.md b/packages/unknownutil-validator/CHANGELOG.md
new file mode 100644
index 00000000..24f63faa
--- /dev/null
+++ b/packages/unknownutil-validator/CHANGELOG.md
@@ -0,0 +1,2 @@
+# @hono/unknownutil-validator
+
diff --git a/packages/unknownutil-validator/README.md b/packages/unknownutil-validator/README.md
new file mode 100644
index 00000000..2b073208
--- /dev/null
+++ b/packages/unknownutil-validator/README.md
@@ -0,0 +1,46 @@
+# Unknownutil validator middleware for Hono
+
+The type validator middleware using [Unknownutil](https://github.com/lambdalisue/deno-unknownutil) for [Hono](https://honojs.dev) applications.
+You can write a schema with unknownutil and check the type of the incoming values.
+
+## Usage
+
+```ts
+import { is } from 'unknownutil'
+import { uValidator } from '@hono/unknownutil-validator'
+
+const schema = is.ObjectOf({
+  name: is.String,
+  age: is.Number,
+})
+
+app.post('/author', uValidator('json', schema), (c) => {
+  const data = c.req.valid('json')
+  return c.json({
+    success: true,
+    message: `${data.name} is ${data.age}`,
+  })
+})
+```
+
+Hook:
+
+```ts
+app.post(
+  '/post',
+  uValidator('json', schema, (result, c) => {
+    if (result.error) {
+      return c.text('Invalid!', 400)
+    }
+  })
+  //...
+)
+```
+
+## Author
+
+Ryotaro "Justin" Kimura <https://github.com/ryoppippi>
+
+## License
+
+MIT
diff --git a/packages/unknownutil-validator/jest.config.js b/packages/unknownutil-validator/jest.config.js
new file mode 100644
index 00000000..f697d831
--- /dev/null
+++ b/packages/unknownutil-validator/jest.config.js
@@ -0,0 +1 @@
+module.exports = require('../../jest.config.js')
diff --git a/packages/unknownutil-validator/package.json b/packages/unknownutil-validator/package.json
new file mode 100644
index 00000000..d3f47609
--- /dev/null
+++ b/packages/unknownutil-validator/package.json
@@ -0,0 +1,37 @@
+{
+  "name": "@hono/unknownutil-validator",
+  "version": "0.1.0",
+  "description": "Validator middleware using unknonwnutil",
+  "main": "dist/cjs/index.js",
+  "module": "dist/esm/index.js",
+  "types": "dist/esm/index.d.ts",
+  "files": [
+    "dist"
+  ],
+  "scripts": {
+    "test": "jest",
+    "build:cjs": "tsc -p tsconfig.cjs.json",
+    "build:esm": "tsc -p tsconfig.esm.json",
+    "build": "rimraf dist && yarn build:cjs && yarn build:esm",
+    "prerelease": "yarn build && yarn test",
+    "release": "yarn publish"
+  },
+  "license": "MIT",
+  "publishConfig": {
+    "registry": "https://registry.npmjs.org",
+    "access": "public"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/honojs/middleware.git"
+  },
+  "homepage": "https://github.com/honojs/middleware",
+  "peerDependencies": {
+    "hono": "3.*",
+    "unknownutil": "^3.9.0"
+  },
+  "devDependencies": {
+    "hono": "^3.1.0",
+    "unknownutil": "^3.9.0"
+  }
+}
diff --git a/packages/unknownutil-validator/src/index.ts b/packages/unknownutil-validator/src/index.ts
new file mode 100644
index 00000000..fbbdd202
--- /dev/null
+++ b/packages/unknownutil-validator/src/index.ts
@@ -0,0 +1,60 @@
+import type { Context, MiddlewareHandler, Env, ValidationTargets, TypedResponse } from 'hono'
+import { validator } from 'hono/validator'
+import { AssertError, ensure, type Predicate, type PredicateType } from 'unknownutil'
+
+export type Hook<T, E extends Env, P extends string> = (
+  result: { data: T; error: undefined } | { data: undefined; error: AssertError },
+  c: Context<E, P>
+) => Response | Promise<Response> | void | Promise<Response | void> | TypedResponse<T>
+
+export const uValidator = <
+  T,
+  S extends Predicate<T>,
+  Target extends keyof ValidationTargets,
+  E extends Env,
+  P extends string,
+  V extends {
+    in: { [K in Target]: PredicateType<S> }
+    out: { [K in Target]: PredicateType<S> }
+  } = {
+    in: { [K in Target]: PredicateType<S> }
+    out: { [K in Target]: PredicateType<S> }
+  }
+>(
+  target: Target,
+  schema: S,
+  hook?: Hook<PredicateType<S>, E, P>
+): MiddlewareHandler<E, P, V> =>
+  validator(target, (value, c) => {
+    let resultUnion: [AssertError, undefined] | [undefined, PredicateType<S>]
+
+    try {
+      resultUnion = [undefined, ensure(value, schema) as PredicateType<S>]
+    } catch (error: unknown) {
+      if (error instanceof AssertError) {
+        resultUnion = [error, undefined]
+      } else {
+        throw new Error(undefined, { cause: error })
+      }
+    }
+
+    const [error, data] = resultUnion
+
+    if (hook) {
+      const hookResult = hook(error ? { data: undefined, error } : { data, error: undefined }, c)
+      if (hookResult) {
+        if (hookResult instanceof Response || hookResult instanceof Promise) {
+          return hookResult
+        }
+        if ('response' in hookResult) {
+          return hookResult.response
+        }
+      }
+    }
+
+    if (error) {
+      return c.json({ success: false, error: error.message }, 400)
+    }
+
+    return value
+  })
diff --git a/packages/unknownutil-validator/test/index.test.ts b/packages/unknownutil-validator/test/index.test.ts
new file mode 100644
index 00000000..bf480294
--- /dev/null
+++ b/packages/unknownutil-validator/test/index.test.ts
@@ -0,0 +1,131 @@
+import { Hono } from 'hono'
+import type { Equal, Expect } from 'hono/utils/types'
+import { is } from 'unknownutil'
+import { uValidator } from '../src'
+
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+type ExtractSchema<T> = T extends Hono<infer _, infer S> ? S : never
+
+describe('Basic', () => {
+  const app = new Hono()
+
+  const schema = is.ObjectOf({
+    name: is.String,
+    age: is.Number,
+  })
+
+  const route = app.post('/author', uValidator('json', schema), (c) => {
+    const data = c.req.valid('json')
+    return c.jsonT({
+      success: true,
+      message: `${data.name} is ${data.age}`,
+    })
+  })
+
+  type Actual = ExtractSchema<typeof route>
+  type Expected = {
+    '/author': {
+      $post: {
+        input: {
+          json: {
+            name: string
+            age: number
+          }
+        }
+        output: {
+          success: true
+          message: string
+        }
+      }
+    }
+  }
+
+  // eslint-disable-next-line @typescript-eslint/no-unused-vars
+  type verify = Expect<Equal<Expected, Actual>>
+
+  it('Should return 200 response', async () => {
+    const req = new Request('http://localhost/author', {
+      body: JSON.stringify({
+        name: 'Superman',
+        age: 20,
+      }),
+      method: 'POST',
+    })
+    const res = await app.request(req)
+    expect(res).not.toBeNull()
+    expect(res.status).toBe(200)
+    expect(await res.json()).toEqual({
+      success: true,
+      message: 'Superman is 20',
+    })
+  })
+
+  it('Should return 400 response', async () => {
+    const req = new Request('http://localhost/author', {
+      body: JSON.stringify({
+        name: 'Superman',
+        age: '20',
+      }),
+      method: 'POST',
+    })
+    const res = await app.request(req)
+    expect(res).not.toBeNull()
+    expect(res.status).toBe(400)
+    const data = (await res.json()) as { success: boolean }
+    expect(data['success']).toBe(false)
+  })
+})
+
+describe('With Hook', () => {
+  const app = new Hono()
+
+  const schema = is.ObjectOf({
+    id: is.Number,
+    title: is.String,
+  })
+
+  app.post(
+    '/post',
+    uValidator('json', schema, (result, c) => {
+      if (result.error) {
+        return c.text('Invalid!', 400)
+      }
+      const data = result.data
+      return c.text(`${data.id} is valid!`)
+    }),
+    (c) => {
+      const data = c.req.valid('json')
+      return c.json({
+        success: true,
+        message: `${data.id} is ${data.title}`,
+      })
+    }
+  )
+
+  it('Should return 200 response', async () => {
+    const req = new Request('http://localhost/post', {
+      body: JSON.stringify({
+        id: 123,
+        title: 'Hello',
+      }),
+      method: 'POST',
+    })
+    const res = await app.request(req)
+    expect(res).not.toBeNull()
+    expect(res.status).toBe(200)
+    expect(await res.text()).toBe('123 is valid!')
+  })
+
+  it('Should return 400 response', async () => {
+    const req = new Request('http://localhost/post', {
+      body: JSON.stringify({
+        id: '123',
+        title: 'Hello',
+      }),
+      method: 'POST',
+    })
+    const res = await app.request(req)
+    expect(res).not.toBeNull()
+    expect(res.status).toBe(400)
+  })
+})
diff --git a/packages/unknownutil-validator/tsconfig.cjs.json b/packages/unknownutil-validator/tsconfig.cjs.json
new file mode 100644
index 00000000..b8bf50ee
--- /dev/null
+++ b/packages/unknownutil-validator/tsconfig.cjs.json
@@ -0,0 +1,8 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "module": "CommonJS",
+    "declaration": false,
+    "outDir": "./dist/cjs"
+  }
+}
\ No newline at end of file
diff --git a/packages/unknownutil-validator/tsconfig.esm.json b/packages/unknownutil-validator/tsconfig.esm.json
new file mode 100644
index 00000000..8130f1a5
--- /dev/null
+++ b/packages/unknownutil-validator/tsconfig.esm.json
@@ -0,0 +1,8 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "module": "ESNext",
+    "declaration": true,
+    "outDir": "./dist/esm"
+  }
+}
\ No newline at end of file
diff --git a/packages/unknownutil-validator/tsconfig.json b/packages/unknownutil-validator/tsconfig.json
new file mode 100644
index 00000000..6c1a3990
--- /dev/null
+++ b/packages/unknownutil-validator/tsconfig.json
@@ -0,0 +1,9 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "rootDir": "./src",
+  },
+  "include": [
+    "src/**/*.ts"
+  ],
+}
\ No newline at end of file