Patent ID: 7886865

Claim:
An electric power steering apparatus comprising: a steering column having inserted therein a steering shaft to which steering torque is transmitted; a reduction gear box coupled to the steering column; and an electric motor that transmits a steering assisting force to the steering shaft via a reduction mechanism in the reduction gear box, wherein: in the reduction gear box, the electric motor is mounted on a motor mounting section formed at an end face in a direction crossing the steering shaft and a control unit for controlling to drive the electric motor is mounted on a control-unit mounting section formed on an outer surface close to the motor mounting section, and the control unit includes at least a control board mounted with a command-value calculating unit that calculates a driving command value of the electric motor and a power module board mounted with a power module involving heat generation that controls to drive the electric motor on the basis of the driving command value from the command-value calculating unit, and the power module board is directly mounted on the control-unit mounting section of the reduction gear box.