The ratio of the angular speed of a pinion shaft to the angular speed of a steering wheel is computed. The steering torque Tst transferred to the steering wheel is computed as a multiplication product of the ratio of angular speed and the steering torque Tm of the pinion shaft. The steering torque .DELTA.Tst transferred to the steering wheel due to actuation of a steered wheel turning angle variable device is computed as a value obtained by subtracting the steering torque Tm from the steering torque Tst. An electric power steering control device is controlled so as to generate a steering torque fluctuation-reducing assist torque corresponding to the steering torque .DELTA.Tst.