To provide a fluid pressure cylinder with a damping mechanism excellent in durability and in shock eliminating capacity by providing a ring closed projected wire to prevent fluid leakage from a fluid sump on a portion where a buffer body and a buffer body support part make contact with each other.

A ring closed projected wire 22 is provided on a portion where a rubber cushion 25 and a buffer body support part (rod 16 or ring groove 28 of piston 15) make contact with each other on a cylinder 1. Consequently, high sealing surface pressure can be provided on a sealing surface, and air leakage from an air reservoir is certainly prevented. Additionally, as a rubber cushion 25 arranged in a floating state can be bent as a whole, too, it is needless to dare to increase a rolling-up degree of a lip part 27. Consequently, stress is hardly concentrated on a specified portion of a root part, etc., of the lip part 27. Accordingly, it is possible to prevent early deterioration of the rubber cushion 25 and to improve its durability.