To make a driver surely and promptly recognize the condition that a vehicle deviates from a traveling path.

A vehicle 10 is provided with a steering motor 20 for generating driving force corresponding to the steering angle θ as assist force when the driver operates a steering wheel 14. Based on the output signals of an image sensor 22, lanes 32 and 34 for separating the traveling path 30 where the vehicle 10 travels are recognized. In the case that wheels provided on the vehicle are on the lanes 32 and 34, a fine vibration component is superimposed on a motor current to be supplied to the steering motor 20. When the fine vibration component is superimposed on the motor current, by the change of the assist force, the steering wheel 14 is finely vibrated. Thus, the driver bodily feels the sensation that the vehicle travels on a rugged road. As a result, the condition that the vehicle 10 deviates from the traveling path 30 is surely and promptly recognized.