To improve the effectiveness of energy without making a refrigerator larger in scale and increasing the production cost in such a refrigerator as to utilize two-dimensional refrigerating cycle.

This refrigerator utilizing dual refrigerating cycle is provided with a heat-source side refrigerant circuit A and a usage side refrigerant circuit B which are connected with each other in such a manner as to be heat- exchanged through a cascade heat exchanger 4. A heat transfer tube for condensing refrigerant integrated with an outdoor heat exchanger 2 is provided on the upstream side of the cascade heat exchanger 4 in the usage side refrigerant circuit B. In the usage side refrigerant circuit B, the usage-side refrigerant discharged from a compressor 11 is condensed by an outdoor heat exchanger 2 and then it is sent to the cascade heat exchanger 4.