A muffler forming member (33) defines a muffler chamber (42). Refrigerant discharged from a cylinder bore (20) is sent to the muffler chamber (42). The muffler forming member (33) is coupled to a circumferential surface (110) of a housing (11) of a compressor (10). An oil separation chamber (36) is defined in a discharge pressure zone (132, 40, 36, 42) of the compressor (10). The oil separation chamber (36) separates the oil from the refrigerant discharged from the cylinder bore (20). The oil separation chamber (36) extends into both the muffler forming member (33) and the housing (11). The oil separation chamber (36) has a refrigerant inlet (403) through which the refrigerant flows into the oil separation chamber (36). The refrigerant inlet (403) is formed in the muffler forming member (33). Therefore, the oil separation chamber (36) is prolonged in the direction from the muffler forming member toward the housing (11), thereby improving the oil separation performance (Fig. 3).