In accordance with a vehicle running condition along a lane and an actual steering angle, a control unit determine a target steering angle to follow the lane, and controls an actual steering torque with an actuator to a target steering torque to achieve the target steering angle. The control unit limits the target steering torque by setting a target torque limit determined in dependence on whether the control steering direction is a steer direction away from a straight ahead neutral position or a return direction toward the straight ahead neutral position, to take account of a self aligning torque.