Abstract: The whole of a refrigerant circuit in which a refrigeration cycle is performed is accommodated in a casing. A heat medium circuit is provided, which is connected to the refrigerant circuit through a utilization-side heat exchanger, and which supplies a heat medium exchanging heat with refrigerant in the heat exchanger, to a predetermined heat utilization target. As the refrigerant of the refrigerant circuit, refrigerant which is represented by a molecular formula C3HmFn (note that “m” and “n” are integers equal to or greater than 1 and equal to or less than 5, and a relationship represented by an expression m+n=6 is satisfied), and which has a single double bond in a molecular structure, or refrigerant mixture containing such refrigerant is used.