PURPOSE: To keep off a noise inside a car room due to vibrations in a rear wheel, by detecting acceleration to be added to a front wheel, while constituting this acceleration and exciting force in the same direction so as to be added to the rear wheel after the elapse of time in response to a car speed.

CONSTITUTION: When a front wheel 12 runs on a projection P on a road surface and thereby exciting force acts thereon, this impact is detected by an acceleration sensor 15 and inputted into a control part 16. Simultaneously a car speed is detected and inputted in this control part 16 which performs the specified operation on the basis of the acceleration information 25, determines a damping subject and compensates it so as to accord with an automobile characteristic, while the control part 16 calculates the time required for running on the projection P by a rear wheel 13 being found from the car speed. And, on the basis of these data, the control part 16 drives an excitor 25 in order to pull up the rear wheel 13. With this constitution, a variation due to the projection P can be prevented from causing it to act on the rear wheel 13, thus a noise insides a car room can be kept back.