A refrigerating machine includes a compressor for compressing a refrigerant, a radiator for radiating heat from the refrigerant discharged from the compressor, an expander for expanding the refrigerant discharged from the radiator, and an evaporator for evaporating the refrigerant discharged from the expander, all connected in series. The refrigerating machine also includes a refrigerant flow regulator for regulating the amount of refrigerant flowing into the expander and a controller for controlling the compressor and the refrigerant flow regulator. When the compressor is stopped, the controller controls the refrigerant flow regulator to reduce the amount of refrigerant flowing into the expander.