To provide a single cylinder type hydraulic shock absorber having a structure mountable without interference even to a mounting part with no allowance without changing the diameter of a cylinder body.

The single cylinder type hydraulic shock absorber in which a spring guide 3 supporting the lower end of a suspension spring 2 is connected to a cylindrical guide member 4 arranged outside the cylinder body 11, is provided with an interference preventing cutout part 9 at a guide member 4 which is a portion close or adjacent to a mounting opening 22 of a lower arm 20 when the single cylinder type hydraulic shock absorber is mounted to the lower arm 20.