A reduction gear ratio n of a reduction gear is multiplied by a steering angular speed by a multiplier, and the deviation e achieved by subtracting a motor rotational speed from the multiplication value is integrated and then multiplied by an integration gain to achieve a current target value. The current target value is added with the multiplication value of the deviation e and a proportional gain in a phase compensator to perform phase compensation. The phase-compensation result is added with the value achieved by differentiating the motor rotational speed and multiplying the differential value thus achieved by a control gain in an inertia compensator to perform inertia compensation. Further, the value achieved by multiplying the motor rotational speed by a control gain is subtracted from the inertia-compensation result in a damping controller to perform damping control, and a final current target value. It is achieved from an adder.