To provide a refrigeration system and an air conditioner for a vehicle having high cooling coefficient of performance for canceling respective nonconformity generated when CO2 gas and HC-based gas are separately used by using mixed refrigerant of the CO2 gas and the HC-based gas.

The refrigeration system is provided with a gas-liquid separating unit 24 separating the mixed refrigerant into a first refrigerant component in a gas phase and a second refrigerant component in a liquid phase, having a first outlet for the first refrigerant component and a second outlet for the second refrigerant component, a first refrigerant flow passage 26 connecting between the first outlet of the gas-liquid separating unit 24 and a suction side of a compressor 18, and a second refrigerant flow passage 26 connecting between the second outlet of the gas-liquid separating unit 24 and the suction side of the compressor 18. Further the refrigerant system is provided with a heat exchange unit 30 interposed in the first and second refrigerant flow passages 26, 28 to recool the first refrigerant component from the first refrigerant flow passage 26.