diff --git a/src/NodeParser/MappedTypeNodeParser.ts b/src/NodeParser/MappedTypeNodeParser.ts
index 31233234..1c353ace 100644
--- a/src/NodeParser/MappedTypeNodeParser.ts
+++ b/src/NodeParser/MappedTypeNodeParser.ts
@@ -43,7 +43,18 @@ export class MappedTypeNodeParser implements SubNodeParser {
         } else if (keyListType instanceof LiteralType) {
             // Key type resolves to single known property
             return new ObjectType(id, [], this.getProperties(node, new UnionType([keyListType]), context), false);
-        } else if (keyListType instanceof StringType || keyListType instanceof SymbolType) {
+        } else if (
+            keyListType instanceof StringType ||
+            keyListType instanceof NumberType ||
+            keyListType instanceof SymbolType
+        ) {
+            if (constraintType?.getId() === "number") {
+                const type = this.childNodeParser.createType(
+                    node.type!,
+                    this.createSubContext(node, keyListType, context)
+                );
+                return type === undefined ? undefined : new ArrayType(type);
+            }
             // Key type widens to `string`
             const type = this.childNodeParser.createType(node.type!, context);
             const resultType = type === undefined ? undefined : new ObjectType(id, [], [], type);
@@ -54,9 +65,6 @@ export class MappedTypeNodeParser implements SubNodeParser {
                 }
             }
             return resultType;
-        } else if (keyListType instanceof NumberType) {
-            const type = this.childNodeParser.createType(node.type!, this.createSubContext(node, keyListType, context));
-            return type === undefined ? undefined : new ArrayType(type);
         } else if (keyListType instanceof EnumType) {
             return new ObjectType(id, [], this.getValues(node, keyListType, context), false);
         } else if (keyListType instanceof NeverType) {
diff --git a/test/valid-data/type-mapped-number/main.ts b/test/valid-data/type-mapped-number/main.ts
new file mode 100644
index 00000000..2d18b788
--- /dev/null
+++ b/test/valid-data/type-mapped-number/main.ts
@@ -0,0 +1 @@
+export type MyObject = Record<number, string>;
diff --git a/test/valid-data/type-mapped-number/schema.json b/test/valid-data/type-mapped-number/schema.json
new file mode 100644
index 00000000..cd0c3baa
--- /dev/null
+++ b/test/valid-data/type-mapped-number/schema.json
@@ -0,0 +1,12 @@
+{
+  "$ref": "#/definitions/MyObject",
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "definitions": {
+    "MyObject": {
+      "additionalProperties": {
+        "type": "string"
+      },
+      "type": "object"
+    }
+  }
+}