To use refrigerant not breaking an ozone layer, and to improve abrasion resistance of a sliding part and lubricity.

A vane 15 is formed of steel or cast iron containing at least chrome (Cr), and a compound of Cr and nitrogen (N) is formed on the front surface of it by nitriding. A roller 12 is formed of cast iron or alloyed steel containing any one or more of Cr, molybdenum (Mo), and nickel (Ni) into the hardness of HRC 40 or more by heat treatment. A cylinder 8 is formed of cast iron containing black lead, sintered alloy, or sintered alloy in which lubricative organic materials are applied or diffused on the front surface. Polyol-ester- oil-group oil or ether-group oil is used as lubricating oil. Refrigerant containing no chlorine (C1) is used as the refrigerant.