Abstract: In a dust cover mounting structure of a hydraulic shock absorber (10), a spring seat (15) is formed in a non-annular outer shape, a standing-up rib (34) is provided in an outer edge thereof, and a mounting portion (51) of a dust cover (50) is formed in a non-annular outer shape profiling an inner periphery of the rib (34) of the spring seat (15) and is received in the inner periphery of the rib (34).