Upon searching control parameter used to adjust damping force of a damper from a map in accordance with damper speed and target damping force decided based on moving condition of the vehicle, the map sets the control parameter, which are relatively higher than the actual damping force characteristics, as map data in the area where the damper speed is less than a predetermined value, the area where the noise has the great influence on the sensor outputs. Therefore, it can be prevented that the control parameter of the damping force is varied largely or varied in a short period by the influence of noise, and the driving stability control of the vehicle can be executed exactly and the noise caused by switching the damping force of the damper can be reduced.