To provide a refrigeration unit of a type taking measures against global warming and saving energy that is capable of reducing the diameter of connecting piping and cutting back the kinds of diameter of the connecting piping while obtaining a COP that is the COP in the case when R22 is used or above by using R32 with a small global warming potential, GWP, as refrigerant.

This device is provided with a compressor 23, the first heat exchanger 22, an expansion means 26 and the second heat exchanger 2, and uses R32 as refrigerant. The diameter of the first connecting piping 42 is set at 2/8 inches, and the diameter of the second connecting piping 41 is set at 3/8 inches with a refrigerating capacity in the range of 2.2 to 5.6 kW. The diameter of the first connecting piping 42 is set at 2/8 inches, and the diameter of the second connecting piping 41 is set at 4/8 inches with a refrigerating capacity in the range of 4.5 to 7.1 kW. The diameter of the first connecting piping 42 is set at 2/8 inches, and the diameter of the second connecting piping 41 is set at 5/8 inches with a refrigerating capacity in the range of 7.1 to 14.0 kW.