A spring force adjusting device for a hydraulic shock absorber includes a cover (13) having a tubular shape, which is arranged on an outer side of a rod (12), a suspension spring (2) arranged on outer peripheries of a cylinder (11) and the cover (13), a cam mechanism (3) which adjusts a spring force, which is arranged on the outer periphery of the cover (13), a top cap (5) mounted on a tip of the rod (12), a junction member (4) sandwiched between the top cap (5) and the cover (13), and a means for preventing relative rotations of the top cap (5), the cover (13), and the junction member (4).