To provide a shock absorber which enables an easy confirmation that fitting allowances above the fixed value have been secured at a fitting part between a fitting member and a fitted part and also enables an easy positioning to a location at which the fitted part can be secured on the fitting member with necessary and sufficient fitting allowances.

In a mounting position adjustment device of a shock absorber, a fitting limit confirmation display part 35 (an annular groove 36) is disposed at the position in which the fitted part 11A can impart a minimum required fitting allowance to the fitting part 32, around the outer surface of the fitted part 11A of a damper tube 11 to which the fitting part 32 of the fitting member 29 on a wheel side is threadedly engaged.