To provide a gas compressor capable of operating stably and efficiently while controlling noise generation by securing lubrication under any condition, and an impregnating treatment method for a member composing the gas compressor.

Plural vanes 15 are retreatably attached on a rotor 9 and the rotor 9 is rotatably provided in a space formed with a cylinder 3 and two side blocks 5, 7 to form a compression chamber. Components thereof are impregnated with refrigerating machine oil L to lubricate mutual sliding parts. The impregnating treatment can be done by dipping each member into refrigerating machine oil L or jetting refrigerating machine oil L on each member with using a nozzle 41.