There is provided a novel electric power steering device capable of continuing a steering assist function as much as possible even in an environment where moisture enters inside a housing of an electric motor due to breakage of a rubber boot and an electrical short circuit phenomenon occurs.
A stator 14 around which a winding is wound is vertically divided into two areas in the direction of gravity, a winding 16 of one system is wound in the upper stator area of the stator 14 while the winding 16 of the other system is wound in the lower stator area of the stator 14, and power of the winding of one system is controlled by an electronic control means 33 of one system while power of the winding of the other system is controlled by an electronic control means 34 of the other system. Even if moisture enters inside the housing of the electric motor due to breakage of the rubber boot, occurrence of the electrical short circuit phenomenon is suppressed at least in the winding wound on the upper side, whereby the steering assist can be continued.