To provide a lower insulator capable of advantageously protecting an absorber seal part of a shock absorber while securing the durability of a dust cover.

A cylindrical part 44 projecting to the inside of the dust cover 28 through a lower end opening of the dust cover 28 is provided integrally with respect to a portion positioned at a radial inner side from an abutment part 42 at the lower end of a coil spring 14 of an insulator main body 36 arranged on a spring seat 24 for supporting the lower end of the coil spring 14. By projecting or retracting operations of a piston rod 18, the cylindrical part 44 is axially overlapped with the dust cover 28 all the time.