A slimmed wheel motor having a brake. The slimmed wheel motor includes a motor device and a braking mechanism. The motor device includes a fixed spindle, a first cover being harnessed on the fixed spindle, and a second cover connecting the first cover. A motor stator and a motor rotor are disposed in the first and the second covers. The braking mechanism, which is disposed at one side of the motor device, includes an electromagnetic coil, an armature plate disposed in the electromagnetic coil, and a brake pad disposed between the armature plate and the second cover. Therefore, a friction force can be induced between the brake pad and the second cover to brake the wheel and to stop the rotation. In this manner, the thickness of the wheel motor is significantly reduced, which can effectively reduce the size and the cost of the wheel motor.