To provide a compressor equipped with shaft sealing device(s) not using a buffer gas.

The compressor has shaft sealing part(s) 10 composed of: a supporting part to support rotatably the main rotating shaft of the compressor through a sliding surface; a communication part 30 provided between the compression chamber 22 of the compressor and the supporting part and admitting insertion of the main shaft; a supplying means 26 to supply a sealing oil to the sliding surface of the supporting part; and a circulating means 28 to circulate the sealing oil from the supporting part to the supplying means, wherein the portion of the main shaft located inside the communication part is furnished with a threaded groove 32 having an opposite threading direction to the rotating direction of the main shaft.