A refrigeration cycle system is provided with a two-cylinder type rotary compressor having one compression mechanism which includes a switching mechanism for switching a back surface side of a blade between a low pressure mode and a high pressure mode and controlling the inner space of the cylinder chamber to the high pressure upon switching at the low pressure mode. In a high load state, a normal operation is performed by switching the pressure of the back surface side of the blade of the one compression mechanism at the high pressure mode. In a low load state, an uncompressed operation is performed by switching the pressure of the back surface side of the blade of the one compression mechanism at the low pressure mode and by controlling the inner space of the cylinder chamber to the high pressure to move the blade away from the roller.