AIR CONDITIONER

An air conditioner for vehicle is provided for the purpose of space saving, comprising a refrigerant cycle 13 having: an evaporator 2 which is disposed in a blowing duct 1 and cools blowing air with refrigerant evaporation; a compressor 3 of setting the evaporated refrigerant at high temperature and high pressure; a refrigerant-to-water heat exchanger 4 of heating cooling water by heat transfer from the refrigerant discharged from the compressor 3; and an expansion device 5 of decompressing the refrigerant discharged from the refrigerant-to-water heat exchanger 4, and a cooling water cycle 14 having: a heater core 6 which is disposed on the downstream side of the evaporator 2 on the basis of a blowing direction in the blowing duct 1 and heats blowing air by the heated cooling water; a radiator 7 of cooling the cooling water; a pump 8 of circulating the cooling water cooled by the radiator 7; a power engine 9 cooled by the cooling water fed by the pump 8; and the refrigerant-to-water heat exchanger 4, wherein the refrigerant cycle 13 performs cooling for dehumidification at performing the operation of heating.