A first observer gain of an actual damping force estimating observer 21 calculates a dynamic characteristic compensating signal, and a second observer gain of an actual vehicle model state amount estimating observer 23 calculates a vehicle model compensating signal, from an output deviation corresponding to a difference between a sprung speed (observation output) provided from a vehicle 2 and an estimated sprung speed (estimated observation output) provided from a vehicle approximation model of the actual vehicle model state amount estimating observer 23. The dynamic characteristic compensating signal is input into a dynamic characteristic providing unit of the actual vehicle model state amount estimating observer 23, and is used for adjustment of the setting of the dynamic characteristic providing unit. Therefore, it is possible to curb time lag occurrence in a control, and thereby perform a vibration control with improved accuracy.