A shock absorber according to the present invention is configured to include: a shock absorber main body in which an outer tube and a rod axially movably inserted into the outer tube are included; a suspension spring formed of a coil spring disposed on the outer periphery of the shock absorber main body; a rod-side spring seat attached to the rod and supporting one end of the suspension spring; an annular tube-side spring seat screwed to a screw portion provided on the outer periphery of the outer tube and supporting the other end of the suspension spring; a slider to be placed on the outer periphery of the outer tube with only an axial movement is permitted; a connecting portion that detachably connects the tube-side spring seat to the slider; and a rotation regulating portion that regulates a rotation of the tube-side spring seat and the slider relative to each other about the axis of the outer tube in a state where the tube-side spring seat and the slider are connected to each other.