To prevent deficient oil separation caused by the foaming phenomenon when a compressor stops.

The oil-injection type compressor comprises an oil-injection type compressor body for injecting oil into the compression space in the process of taking air or gas into the compressor body 3 to be compressed and discharging the acting fluid of air or gas and oil, a receiver tank 5, and an oil separator 6 for separating air or gas and oil in the acting fluid. An acting fluid inlet 13 is formed on the side wall 12 of the receiver tank 5, and nearly cylindrical swirling guide boards 16 is attached to the inner side of the acting fluid inlet for forming a swirling space 20 inside the inner wall 19 of the receiver tank. In the swirling space, a swirling channel for the acting fluid is formed facing the acting fluid inlet 13, and an acting fluid takeout port 21 is formed in the receiver tank 5. The oil separator 6 is made to communicate with the takeout port. In addition, an intake tube 25 for introducing the acting fluid is disposed on the inner side of the receiver tank of the takeout port 21. An end opening 26 of the intake tube is disposed inside the swirling guide board 20 and made to face a lid 15 attached to an upper opening 14 of the receiver tank 5.