A suspension device includes a piston rod having a projecting part projecting from one end of a cylinder of a shock absorber to the outside of the cylinder, a lower mount rubber provided in the piston rod, and a cover plate provided in the piston rod and configured to transmit a shock received by the piston rod to the lower mount rubber, the lower mount rubber includes an inner circumferential groove configured to restrict the cover plate from being displaced with respect to the lower mount rubber in a state in which the piston rod is not arranged inside the lower mount rubber and the cover plate and the cover plate is fixed around the projecting part of the piston rod in a state in which the piston rod is arranged inside the cover plate.