To provide a brake device of an in-wheel motor which reduces the size and weight of an in-wheel type driving mechanism, and reduces load exerted on a bearing of a wheel shaft.

The wheel shaft 14 is supported by the interior of an inner housing 12 constituting the brake device 21 through the bearing 13. A hub 15 is engagedly fixed to the wheel shaft 14, and a driving wheel 16 is connected to the hub 15. An inner stator 18 is disposed on the outer peripheral surface of the inner housing 12. A permanent magnet 20 is attached to the outer peripheral surface of the hub 15 through an outer housing 19. A brake drum 12a is integrally formed in an opening of the inner housing 12 on the side opposite the hug 15. A brake mechanism 46 is mounted on an inner end of the wheel shaft 14. The rotation of the wheel shaft 14 is braked by pressing first and second brake shoes 25 and 26 of the brake mechanism 46 against an inner peripheral surface 12b of the brake drum 12a.