Abstract: To keep low the cross frequency of current feedback control and provide a good steering feeling, a first operation expression is selected when a difference &xgr; between a current instruction value computed based on a steering state of a steering wheel and a traveling state of a vehicle and a motor drive current value supplied from a battery to a motor for providing assist force to a system for transmitting power from the steering wheel to the wheels is larger than a predetermined value Th1, a second operation expression is selected when the difference &xgr; is smaller than the predetermined value Th1, and the difference &xgr; is corrected using the selected operation expression.

Abstract: A control apparatus for a motor-driven power steering system of a motor vehicle controls the steering system such that a steering torque required to be applied by a driver is prevented from increasing abruptly or steeply even when generation of an assist torque applied to the steering system for assisting the driver in steering operation is to be stopped.