To reconcile traveling stability and comfortableness in a high order by a damping characteristic suitable for a traveling condition by calculating the damping characteristic on the basis of detected acceleration, comparing this calculation value with a reference value, and renewing the damping characteristic calculated on the basis of a comparing result as a new reference value.

An actual vehicle damping characteristic does not coincide with a demand damping characteristic, and individually fluctuates. Then, a controller 20 stores reference acceleration of car body vibration and a reference damping characteristic corresponding to it, and arithmetically operates a damping characteristic so that acceleration of a vehicle falls within a prescribed acceleration range. The result is outputted to a damper 6 as an orifice signal for indicating a shape of an orifice for deciding the damping characteristic, and the damper 6 to which the orifice signal is inputted switches the orifice to change the damping characteristic.