Abstract: A fluid compressor comprises a cylinder block, a driving shaft rotatably mounted in the cylinder block by means of thrust bearings and radial bearings, an inclined disk rigidly secured to the driving shaft, pistons slidably disposed in cylinder bores formed in the cylinder block, and shoes for operably connecting the inclined disk to the pistons, which are reciprocally moved in the cylinder bores when the inclined disk is rotated to pressurize gaseous fluid for cooling. In order to accommodate the inclined disk, the cylinder block has a housing, which is provided with recesses or grooves on the opposite axial end surfaces to catch the lubrication oil flowing along the inner wall of the housing. Oil ports or passages are also provided for introducing the oil from the recesses or grooves to the radial bearings. Sliding bearings may be used as the radial bearings. Such a sliding bearing may be provided with an oil guide groove or ball indents on the inner peripheral wall thereof.