PURPOSE: To prevent lubrication oil from leaking, in a compressor for vehicle cooling devices, etc. by partitioning the inside of a compressing mechanism section, coolant inlet and outlet sections from each other, to form a seal chamber, and by maintaining the pressure in the seal chamber always at a predetermined value with the use of a pressure regulating valve.

CONSTITUTION: A vane type rotary compressor incorporates in its housing 21 a compressing mechanism section 23 in which is rotatably disposed a rotor 28 composed of a plurality of vanes 27 that are fitted in a cam ring 24 having both ends sealed off by side plates 25, 26, retractably in the radial direction of the rotor. In this arrangement, a seal ring 37 is fitted in a part in which the main rotary shaft 31 of the rotor 28 pierces through a side plate 25. Further, a mechanical seal 38 is fitted in a part in which the rotary shaft 31 pierces through a front cover 22. A seal chamber 40 is formed around the rotary shaft 31 between these sealing members 37, 38, and lubrication oil is charged into the chamber 40 to lubricate necessary parts. Further, the seal chamber 40 is communicated with a coolant suction port 41 through a check valve 43 to maintain the pressure in the seal chamber 40 at a predetermined value.