In an electric power steering device, a control unit includes: a power module including a plurality of switching elements configured to supply current to motor windings of a motor; a control board configured to output a control signal to each of the plurality of switching elements; a housing forming an outer case of the control unit; a power supply connector; and a signal connector. The control board is provided in parallel to the axial direction of the output shaft of the motor, and a projection is formed at a bottom portion on the non-output side of the housing so as to protrude to the non-output side. A non-output side end portion of the control board is inserted into the projection, and the power supply connector and the signal connector are provided in a region other than the projection of an outer wall surface of the bottom portion.