A suspension device of this type, as is disclosed in Japanese Patent Laid-Open Publication No. Hei 08 (1996)-197931, is made up of a coil spring as a suspension spring which supports a vehicle body resiliently, a screw shaft engaged threadably and rotatably with a ball screw nut which is connected to an axle side, and a motor connected to one end of the screw shaft and also connected to the vehicle body side. With rotational torque generated by the motor, a relative movement between the vehicle body and the axle is controlled actively.