A compressor includes a compressing mechanism, a discharge chamber, a housing accommodating the compressing mechanism and the discharge chamber, a discharge port communicating with the discharge chamber through a discharge passage and also with an external refrigerant circuit, a muffler formed by an expanded space disposed on the discharge passage, and a check valve disposed on the discharge passage. The pressure loss caused by the discharge passage is less than that in the known compressor. The check valve is disposed in the muffler to open and close an inlet of the muffler, and the muffler is formed by the housing and a cover independent of and connected to the housing.