The present invention provides a refrigeration unit, which is provided with a compressor with controllable revolution rate for compressing refrigerant; a condenser for cooling the compressed refrigerant; an expansion valve for regulating the flux of the refrigerant; and an evaporator performing the heat exchanger between the refrigerant and the cooling object. When the suction pressure of the compressor is larger than the prescribed speed governing pressure, or the temperature of the cooling object is higher than the prescribed speed governing temperature, the revolution rate of the compressor is maintained to a prescribed speed governing revolution rate lower than the rated speed during the prescribed speed governing period. According to such a composition, a refrigeration device having a smooth start can be provided.