A freezer (1) comprising a plurality of utilization−side heat exchangers (41, 45, 51) such as for air conditioning and refrigeration·freezing purposes, a 4−way switching valve (3C) and a plurality of check valves (7) disposed on the suction side of a compression mechanism (2D, 2E) composed of three compressors (2A, 2B, 2C) so as to switch the operating state, wherein the compressors (2A, 2B, 2C) used on the air conditioning side and on the refrigeration·freezing side are respectively limited in number to two at a maximum, thereby simplifying the circuit arrangement with the check valves (7) on the suction side of the compression mechanism (2D, 2E) reduced in number to one or two, thus preventing the generation of sound due to chattering in the check valves (7) and also preventing a decrease in performance due to a pressure loss on the suction side.
