PURPOSE: To reduce a load on a sliding surface near the opening of spherical recess of a piston and decrease spherical abrasion generated on the spherical recess of the piston by a method wherein the annular section of protruded spherical surface of the shoe near the plane thereof is formed so as to be a retreated spherical surface, retreated radially than the other section of the spherical surface of the shoe.

CONSTITUTION: The semi-spherical shoe 1 contacts slidingly with the spherical recess 21 of piston 2 of a swash plate type compressor while the sliding surface of the swash plate contacts slidingly with the plane 15 of the shoe 1. The annu lar section 12 of spherical surface near the plane of the shoe 1 is formed so as not to be contacted slidingly with the section near the opening of spherical recess 21 of the piston 2. For this purpose, the annular section 12 is formed so as to be the retreated spherical surface, retreated radially from the basic spherical surface having the same radius of curvature as the most of the other spherical surface 11.