PURPOSE: To reduce the friction loss of sliding parts by forming a lubrication hole communicating with sliding parts of an eccentric shaft and of a rolling piston or the like, and lightly pressing a cover onto the end face of a side housing tightly clamped on a cylinder side opposite to a motor.

CONSTITUTION: The rotation of an eccentric shaft 1 makes a rolling piston 3 roll along the inner wall of a compression space 4, and compress and discharge intake gas through a partition plate 5 energized by a spring 12. In this case, since a space 11 formed of an eccentric shaft 1 borne through side housings 6a, 6b and the rolling piston 3 is kept at a medium degree between low pressure and high one, lubricating oil is drawn through a lubrication hole 7 communicating with the space 11, and supplied to sliding parts, but a cover 13 lightly pressed onto the side housing 6b prevents high pressure gas from flowing into said space 11 through a clearance between the eccentric shaft 1 and the side housing 6b. An oil supply can be therefore kept constant to improve the sealing of the lubricating oil against refrigerant and reduce the friction loss of sliding parts.