In view of the matter that an abnormality occurred in an operating portion of a control system comes out in an early stage as a result of the control, while it takes a time for an abnormality occurred in the generation of a controlling amount for controlling the operation of an operating portion to come out, in ceasing the control when an abnormality has occurred in the control system the controlling amount is decreased at a higher speed when the abnormality of the controlling amount was judged than a speed at which the operation of the operating device is decreased when the abnormality of the operating device was judged.