An electric power steering device includes a motor housing of an electric motor. An annular seal accommodating portion is formed around an external terminal forming part of a connector assembly, and filled with a liquid sealing agent. A fixing member fixes the connector assembly to a fixing part of an end face part of the motor housing. A liquid sealing agent guiding passage is formed with the annular seal accommodating portion, and allows the liquid sealing agent to flow to the fixing member. A metal cover includes: a bottom part including: an exposure hole through which the external terminal forming part is exposed to outside; and an annular reinforcing projecting portion formed at an edge of the exposure hole, and accommodated in the annular seal accommodating portion; and a lateral peripheral part angled from the bottom part, and forming an opening for fixation to the end face part.