The present invention relates to a vehicle air conditioner and, more specifically, to a vehicle air conditioner which supplies, to a variable heat exchanger, condensate water and air, that have been blown by means of a supply part and passed through an evaporator, so as to enable sub-cooling and overall performance of the variable heat exchanger to be improved during cooling, thereby further increasing cooling performance, and which may use air and condensate water as a heat-absorbing heat source during heating so as to further increase the heat absorption amount of the variable heat exchanger, so that heating performance may be further increased, and thus overall power consumption for air conditioning may be reduced and an increase in heat pump system performance may be promoted.