Compression apparatus

A compression apparatus comprising

• a plurality of compressors connected in series in a refrigerant circuit that is configured to circulate a refrigerant;
• an oil separator provided in a first discharge passage connected to a first discharge outlet of one compressor of the plurality of compressors, directly upstream of another compressor of the plurality of compressors, and configured to separate oil from the refrigerant discharged from the one compressor and to cause the refrigerant separated from the oil to flow downstream;
• an oil return passage provided with the one compressor and configured to return the oil separated by the oil separator to an intake passage of the one compressor;
• a second discharge outlet provided in the one compressor;
• and
• a second discharge passage configured to connect the second discharge outlet to an inlet of the oil separator, the second discharge passage merging into the first discharge passage upstream of the oil separator.