A refrigerating cycle apparatus and a method of operating the same are provided. For a refrigerating cycle having a plurality of compressors connected in series for multi-stage compression, an inner space of each compressor and a pipe of the refrigerating cycle may be connected via an oil collection pipe, and oil may be discharged into the refrigerating cycle by pressure reversal during a pressure balancing operation, so as to allow the discharged oil to be collected into a high-stage compressor or a low-stage compressor. Accordingly, an amount of oil may be uniformly maintained in each of the plurality of compressors to prevent losses due to friction and/or increases in power consumption due to a lack of oil in one or more of the compressors. The structure of a device and pipes for performing oil balancing between the compressors may be simplified to enhance efficiency of the compressors.