PURPOSE: To expand the performance range of a refrigeration cycle device by a method wherein the device is provided with a low boiling point refrigerant circuit, sending low boiling point refrigerant reserved in an adsorption tower to an evaporator, and a high boiling point refrigerant circuit, sending high boiling point refrigerant reserved in a tank to the evaporator.

CONSTITUTION: Low boiling point refrigerant, constituting mixed refrigerant, is retrieved into a low boiling point refrigerant circuit 19 while high boiling point refrigerant is reserved in a high boiling point liquefied refrigerant reserving tank 18. The high boiling point refrigerant, reserved in the reserving tank 18, is reserved as it is whereby the composition of the refrigerant, circulating in a refrigerating cycle, becomes rich in the low boiling point refrigerant and the refrigerating cycle is operated by low boiling point refrigerant rich operation. On the other hand, the high boiling point refrigerant, reserved in the reserving tank 18, is made to flow into a high boiling point refrigerant circuit 20 constituting the refrigeration cycle to circulate it in the refrigeration cycle while the low boiling point refrigerant is adsorbed and reserved in an adsorption tower 11 whereby the composition of the circulating refrigerant becomes rich in the high boiling point refrigerant and high boiling point refrigerant rich operation may be effected.