To perform pressure control so that refrigerant in gas-phase state can regularly stably keep non-condensation pressure following rotating speed fluctuation of a compressor in a refrigeration unit which adapts non-condensation heating system to keep the heat in the inside.

The refrigeration unit is adapted so that non-condensation heating operation of introducing refrigerant in gas-phase state discharged from the compressor 1 to an evaporator 17 while decompressing to a temperature-controlled space internal temperature saturating pressure or less of a keep-warm storage can be performed. This refrigeration unit comprises a hot gas bypass pipe 6 introducing the refrigerant in gas-phase state to the evaporator 17 while bypassing a capacitor 13 and an electronic expansion valve 17, capillary tubes 7A and 7B decompressing the refrigerant distributed in the hot gas bypass pipe 6 to the temperature-controlled space internal temperature saturating pressure or less; and hot gas solenoid valves 7A and 7B opening and closing the hot gas bypass pipe 6 to intermit the distribution of the refrigerant. The decompressing capability of the capillary tubes 7A and 7B can be varied according to the rotating speed of the compressor 11.