A refrigeration cycle device for a vehicle includes a refrigerant circuit, in which a zeotropic refrigerant mixture is circulated, including a utilization heat exchanger including a first heat exchange portion and a second heat exchange portion disposed in series with the first heat exchange portion in a direction in which the zeotropic refrigerant mixture flows in the refrigerant circuit. The first heat exchange portion is disposed on an upstream side of the second heat exchange portion in a direction in which the zeotropic refrigerant mixture flows when the utilization heat exchanger functions as an evaporator of the zeotropic refrigerant mixture.

A heat-source-side circuit of a heat source unit includes a low-stage compressor, a high-stage compressor, a heat-source-side heat exchanger, a receiver, and a venting passage. The venting passage connects an upper portion of the receiver with an inlet of the high-stage compressor. A determination unit of the heat source unit determines that the amount of the refrigerant charged in a refrigerant circuit is excessive based on the pressure and the degree of superheat of the refrigerant sucked into the high-stage compressor.