In a suspension system for a vehicle comprising a shock absorber of which damping force characteristics can be changed into four or more characteristics, detecting means detect the oscillation frequency range of the sprung member of the vehicle and a bumpy road. From the four or more damping force characteristics of the shock absorber, the number of characteristics on the higher level side are limited to two or so when the sprung member is in a low frequency oscillation range, that of the characteristics on the lower level side are limited to two or so when the sprung member is in a high frequency oscillation range, and that of the characteristics on the medium level side are limited to two or so when a road is bumpy. The damping force characteristic of the shock absorber is selected and changed on the basis of a given control rule only within the limited damping force characteristics. Thus, it is possible to prevent noise and oscillation from being caused by the large change of the damping force characteristic. Furthermore, there can be obtained comfortableness to ride in and stability on a high level.