A refrigerating unit capable of optimum operation with respect to load by finely changing the operating capacity in response to changes in load, and offering energy saving effects. The refrigerating unit has a scroll type inverter-driven compressor and scroll type constant-speed compressors; a pressure sensor installed on the suction side; a circuit for starting the inverter-driven compressor first; and a circuit for deciding the driving frequency of the compressor and the number of constant-speed compressors to operate, based on a suction pressure value detected by the pressure sensor after the compressor was started.