A refrigeration cycle device comprising: a main refrigerant circuit formed by sequentially connecting, to one another through a pipe, a compression mechanism composed of a compression rotation element (11a, 11b), a usage-side heat exchanger for heating usage-side heat medium by refrigerant discharged from the compression rotation element, an intermediate heat exchanger, a first expansion device and a heat source-side heat exchanger; a bypass refrigerant circuit comprising a second expansion device branched off from the pipe between the usage-side heat exchanger and the first expansion device; a low pressure-side detector for detecting temperature of the refrigerant on a low pressure side of the main refrigerant circuit, or pressure of the refrigerant on the low pressure side of the main refrigerant circuit, or temperature of air which passes through the heat source-side heat exchanger; wherein the bypass refrigerant circuit is configured such that refrigerant in the bypass refrigerant circuit, branched from the pipe between the usage-side heat exchanger and the first expansion device is decompressed by the second expansion device, thereafter, heat of the refrigerant is exchanged with that of the refrigerant flowing through the main refrigerant circuit by the intermediate heat exchanger, and the refrigerant joins up with refrigerant which is in middle of a compression operation of the compression rotation element (11a, 11b); the refrigeration cycle device further comprising a control device, wherein when a detected value detected by the low pressure-side detector is lower than a predetermined value, the control device adjusts opening degrees of the first expansion device and the second expansion device, and the control device makes a flow rate of refrigerant flowing through the second expansion device larger than a flow rate of refrigerant flowing through the first expansion device. a main refrigerant circuit formed by sequentially connecting, to one another through a pipe, a compression mechanism composed of a compression rotation element (11a, 11b), a usage-side heat exchanger for heating usage-side heat medium by refrigerant discharged from the compression rotation element, an intermediate heat exchanger, a first expansion device and a heat source-side heat exchanger; a bypass refrigerant circuit comprising a second expansion device branched off from the pipe between the usage-side heat exchanger and the first expansion device; a low pressure-side detector for detecting temperature of the refrigerant on a low pressure side of the main refrigerant circuit, or pressure of the refrigerant on the low pressure side of the main refrigerant circuit, or temperature of air which passes through the heat source-side heat exchanger; wherein the bypass refrigerant circuit is configured such that refrigerant in the bypass refrigerant circuit, branched from the pipe between the usage-side heat exchanger and the first expansion device is decompressed by the second expansion device, thereafter, heat of the refrigerant is exchanged with that of the refrigerant flowing through the main refrigerant circuit by the intermediate heat exchanger, and the refrigerant joins up with refrigerant which is in middle of a compression operation of the compression rotation element (11a, 11b); the refrigeration cycle device further comprising a control device, wherein when a detected value detected by the low pressure-side detector is lower than a predetermined value, the control device adjusts opening degrees of the first expansion device and the second expansion device, and the control device makes a flow rate of refrigerant flowing through the second expansion device larger than a flow rate of refrigerant flowing through the first expansion device.