In an air cooling mode of cooling air as a fluid to be heat-exchanged, a refrigeration cycle device is provided to perform switching to a refrigerant circuit in which a high-pressure refrigerant exchanging heat with outside air in an exterior heat exchanger and dissipating heat therefrom flows into an accumulator serving as a gas-liquid separator. In an air heating mode of heating the air, the refrigeration cycle device also performs switching to another refrigerant circuit that allows a low-pressure refrigerant decompressed by a first expansion valve to flow into the accumulator. Thus, even in any operation mode, a difference between a refrigerant temperature in the accumulator and the outside air temperature is reduced to thereby suppress the degradation of performance of the refrigeration cycle device due to the unnecessary transfer of heat between the refrigerant in the accumulator and the outside air.