PURPOSE: To realize a stable travelling characteristic by preventing idling of a driving axle by increasing a load applied on the driving axle by reducing a load applied to a driven axle at the time of starting and accelerating.

CONSTITUTION: A control circuit 9 judges whether current car speed exceeds a specified value or not by taking output from a load sensor 2 or taking output from a car speed sensor 3 in the case when a movable load is lower than a set value. When the current car speed does not exceeds the specified value, a load allotment of a driving axle 5 is increased by controlling load addition to the driving axle 5. In the case when the car speed exceeds the specified value, additional control to the driving axle 5 is prohibited and a load to the driving axle 5 and a driven axle 6 is uniformed. A time differential value of the car speed is computed until a vehicle reaches the specified value after the vehicle starts, and in the case when the value exceeds the specified value, a load allotment to the driving axle 5 is continuously increased until the car speed exceeds a second specified value. Consequently, it is possible to realize a stable travelling characteristic.