PURPOSE:To enlarge the range of cooling and/or heating capacity, carry out highly efficient cooling and/or heating operation, reduce the noise, abrasion, vibration and the like and prolong the life of the device by a method wherein a refrigerant control means, controlling the ratio of composition of mixture of refrigerant to change refrigerating capacity at the time of refrigerating operation, is provided. CONSTITUTION:A refrigerating device is provided with a compressor 1, a four-way valve 5, an indoor heat exchanger 7 and a refrigerant control means consisting of a storage tank 9, a pressure reducing device 11 and an outdoor heat exchanger 13, which are connected and communicated through refrigerant pipes 15. A control unit 27 determines an operating number of rotation by an air-conditioning load signal from an air-conditioning load detecting unit S to control the compressor 1 while the amount of opening and closing of a control valve 23 is set and controlled by a relation between the air-conditioning load and the number of rotation of the compressor 1. According to this method, control from a heating temperature, whereat low-boiling point refrigerant is gasified, to another heating temperature, whereat high-boiling point refrigerant is gasified, can be carried out and the reserving ratio of refrigerant in the reserving tank 9 can be increased in accordance with the ratio of gasified refrigerant whereby an operation mode, in which the ratio of composition of low-boiling point refrigerant and high-boiling point refrigerant in a circulating cycle is increased, can be obtained.