To reduce relative friction between a cylinder and a piston by causing surface roughness of the cylinder to be proper and by improving wear resistance of a piston ring in a cylinder-piston sliding structure and a piston-cylinder sliding structure.

In the cylinder-piston sliding structure including a piston 3 having a skirt 3a, a cylinder 2 slidably and reciprocally receiving the piston 3 via lubrication oil, and piston rings 5, 6, 7 stretched on an outer circumferential surface of the piston 3 along a circumferential direction, the cylinder 2 is formed in a cylindrical shape, the piston rings 5, 6, 7 are formed in a ring shape capable of sliding relative to an inner surface 2a of the cylinder 2 via the lubrication oil, the sliding surface of the cylinder 2 with the piston rings 5, 6, 7 is formed as a mirror surface, and amorphous hard carbon coating 11 is formed on sliding surfaces of the piston rings 5, 6, 7.