A vehicle air conditioner capable of making a determination that the dehumidification is unnecessary in a vehicle interior early to make a prompt transition from a dehumidifying mode to a heating mode and reduce power consumption is provided. A control device executes a heating mode to let a refrigerant discharged from a compressor 2 radiate heat in a radiator, decompress the refrigerant, and then let the refrigerant absorb heat in an outdoor heat exchanger 7, and a dehumidifying mode to let the refrigerant flow into the outdoor heat exchanger without flowing to the radiator to radiate heat therein, decompress the refrigerant, and then let the refrigerant absorb heat in a heat absorber 9 and let an auxiliary heater 23 generate heat. The control device shifts from the dehumidifying mode to the heating mode on the basis of the heat absorber suction air temperature Tevain being lowered more than a target heat absorber temperature TEO.