A bump cap includes: a tubular main body part; and three or more protrusions provided at different positions in a circumferential direction of an inner circumference of the main body part. A plurality of protrusions are press-fit protrusions having a radial height higher than a radial height of the other protrusions, and the number of the press-fit protrusions are smaller than the number of the other protrusions, and the bump cap is configured to be mounted on an outer circumference of an outer shell of a shock absorber in state where the press-fit protrusions are pushed against the outer circumference of the outer shell.