There is disclosed a vehicle air conditioner capable of preventing or inhibiting deterioration of a vehicle interior heating capability which is caused by frost formation to an outdoor heat exchanger. The vehicle air conditioner includes a compressor 2, an air flow passage 3, a radiator 4, a heat absorber 9, and an outdoor heat exchanger 7, and executes a heating mode in which a refrigerant discharged from the compressor radiates heat in the radiator, is decompressed and then absorbs heat in the outdoor heat exchanger. The vehicle air conditioner includes an accumulator 12 disposed on a suction side of the compressor, and a bypass circuit 24B disposed from a refrigerant outlet side of the radiator to an inlet side of the accumulator. A controller has a mode in which the refrigerant flowing out from the radiator is passed through the bypass circuit, does not flow through the outdoor heat exchanger, but flows into the accumulator.