diff --git a/deno_dist/types.ts b/deno_dist/types.ts
index 00b91fb4..d2f9d8d1 100644
--- a/deno_dist/types.ts
+++ b/deno_dist/types.ts
@@ -1627,7 +1627,9 @@ type ExtractParams<Path extends string> = string extends Path
   ? { [K in Param | keyof ExtractParams<`/${Rest}`>]: string }
   : Path extends `${infer Start}:${infer Param}`
   ? { [K in Param]: string }
-  : {}
+  : never
+
+type FlattenIfIntersect<T> = T extends infer O ? { [K in keyof O]: O[K] } : never
 
 export type MergeSchemaPath<OrigSchema extends Schema, SubPath extends string> = {
   [P in keyof OrigSchema as MergePath<SubPath, P & string>]: {
@@ -1636,8 +1638,10 @@ export type MergeSchemaPath<OrigSchema extends Schema, SubPath extends string> =
       output: infer Output
     }
       ? {
-          input: Input extends { param: infer Params }
-            ? { param: Params & ExtractParams<SubPath> }
+          input: Input extends { param: infer _ }
+            ? ExtractParams<SubPath> extends never
+              ? Input
+              : FlattenIfIntersect<Input & { param: ExtractParams<SubPath> }>
             : RemoveBlankRecord<ExtractParams<SubPath>> extends never
             ? Input
             : Input & { param: ExtractParams<SubPath> }
@@ -1648,6 +1652,8 @@ export type MergeSchemaPath<OrigSchema extends Schema, SubPath extends string> =
 }
 
 export type AddParam<I, P extends string> = ParamKeys<P> extends never
+  ? I
+  : I extends { param: infer _ }
   ? I
   : I & { param: UnionToIntersection<ParamKeyToRecord<ParamKeys<P>>> }
 
diff --git a/src/types.test.ts b/src/types.test.ts
index 3103f510..8533f836 100644
--- a/src/types.test.ts
+++ b/src/types.test.ts
@@ -6,6 +6,7 @@ import { createMiddleware } from './helper'
 import { Hono } from './hono'
 import { poweredBy } from './middleware/powered-by'
 import type {
+  AddParam,
   Env,
   ExtractSchema,
   Handler,
@@ -475,8 +476,57 @@ describe('For HonoRequest', () => {
   })
 })
 
-describe('merge path', () => {
-  test('MergePath', () => {
+describe('AddParam', () => {
+  it('Should add params to input correctly', () => {
+    type Actual = AddParam<
+      {
+        param: {
+          id: string
+        }
+      } & {
+        query: {
+          page: string
+        }
+      },
+      '/:id'
+    >
+    type Expected = {
+      query: {
+        page: string
+      }
+    } & {
+      param: {
+        id: string
+      }
+    }
+    type verify = Expect<Equal<Expected, Actual>>
+  })
+})
+
+describe('ToSchema', () => {
+  it('Should convert parameters to schema correctly', () => {
+    type Actual = ToSchema<'get', '/:id', { param: { id: string }; query: { page: string } }, {}>
+    type Expected = {
+      '/:id': {
+        $get: {
+          input: {
+            param: {
+              id: string
+            }
+            query: {
+              page: string
+            }
+          }
+          output: {}
+        }
+      }
+    }
+    type verify = Expect<Equal<Expected, Actual>>
+  })
+})
+
+describe('MergePath', () => {
+  it('Should merge paths correctly', () => {
     type path1 = MergePath<'/api', '/book'>
     type verify1 = Expect<Equal<'/api/book', path1>>
     type path2 = MergePath<'/api/', '/book'>
@@ -486,8 +536,10 @@ describe('merge path', () => {
     type path4 = MergePath<'/api', '/'>
     type verify4 = Expect<Equal<'/api', path4>>
   })
+})
 
-  test('MergeSchemaPath', () => {
+describe('MergeSchemaPath', () => {
+  it('Should merge schema and sub path correctly', () => {
     type Sub = ToSchema<
       'post',
       '/posts',
@@ -537,7 +589,7 @@ describe('merge path', () => {
     type verify = Expect<Equal<Expected, Actual>>
   })
 
-  test('MergeSchemePath - with params and the subpath does not have params', () => {
+  it('Should merge schema which has params and sub path does not have params', () => {
     type Actual = MergeSchemaPath<
       {
         '/': {
@@ -546,6 +598,9 @@ describe('merge path', () => {
               param: {
                 id: string
               }
+              query: {
+                page: string
+              }
             }
             output: {}
           }
@@ -560,6 +615,9 @@ describe('merge path', () => {
             param: {
               id: string
             }
+            query: {
+              page: string
+            }
           }
           output: {}
         }
diff --git a/src/types.ts b/src/types.ts
index 7bb1cd92..18d5debb 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1627,7 +1627,9 @@ type ExtractParams<Path extends string> = string extends Path
   ? { [K in Param | keyof ExtractParams<`/${Rest}`>]: string }
   : Path extends `${infer Start}:${infer Param}`
   ? { [K in Param]: string }
-  : {}
+  : never
+
+type FlattenIfIntersect<T> = T extends infer O ? { [K in keyof O]: O[K] } : never
 
 export type MergeSchemaPath<OrigSchema extends Schema, SubPath extends string> = {
   [P in keyof OrigSchema as MergePath<SubPath, P & string>]: {
@@ -1636,8 +1638,10 @@ export type MergeSchemaPath<OrigSchema extends Schema, SubPath extends string> =
       output: infer Output
     }
       ? {
-          input: Input extends { param: infer Params }
-            ? { param: Params & ExtractParams<SubPath> }
+          input: Input extends { param: infer _ }
+            ? ExtractParams<SubPath> extends never
+              ? Input
+              : FlattenIfIntersect<Input & { param: ExtractParams<SubPath> }>
             : RemoveBlankRecord<ExtractParams<SubPath>> extends never
             ? Input
             : Input & { param: ExtractParams<SubPath> }
@@ -1648,6 +1652,8 @@ export type MergeSchemaPath<OrigSchema extends Schema, SubPath extends string> =
 }
 
 export type AddParam<I, P extends string> = ParamKeys<P> extends never
+  ? I
+  : I extends { param: infer _ }
   ? I
   : I & { param: UnionToIntersection<ParamKeyToRecord<ParamKeys<P>>> }