An active actuator is interposed between the unsprung mass and the sprung mass of a vehicle, and a controller selectively extends and retracts the actuator at a prescribed acceleration so as to selectively apply an additional contact load to the wheel by making use of the inertial force of the sprung mass and/or the unsprung mass of the vehicle. A particularly advantageous result can be achieved by increasing the tire contact load when the wheel is about to lock up when braking. The present invention can thus reduce the braking distance for the given road condition.