To escape easily from a stuck state regardless of the driving technique of a driver.

When the vehicle speed V is less than the threshold VES continuously for the specified time in spite of depressing an accelerator pedal, it is so judged that a vehicle fell into an unoperatable state by normal operation (stuck state) such as a wheel being caught into a recess (S102-S114). Upon judging the vehicle to have fallen into the stuck state, the torque of an assist motor fitted to a driving shaft is made the value corresponding to the depressed quantity of the accelerator pedal when the vehicle speed V is the value 0 or more (step S118) and made the value 0 when the vehicle speed is less than the value 0 (step S120). With this control, the vehicle is longitudinally shaken and escapes from the stuck state when the energy of this shaking exceeds the energy of escaping from the recess. As a result, anyone can easily make the vehicle escape from the stuck state regardless of driving technique.