Abstract: An oil separator which is accomodated within a compressor utilized in a comparatively small refrigerator such as an automobile air conditioner. Generally, an oil separator is arranged next to an outlet port of the compressor in order to separate lubricant intermixed in the compressed gaseous refrigerant therefrom. The oil separator is provided with a double barrelled cylindrically shaped separation chamber, the one end of which is blocked and the other end of which is connected with multi layered filter elements and further is blocked by an end plate thereon. The separation chamber is provided with a gas conduit opening in the tangential direction thereof to communicate with a passage. Furthermore a pipe is projected extending over one end of said separation chamber to a pressure chamber in the compressor.