There is disclosed an air conditioning device for vehicle in which in a defrosting mode to defrost an outdoor heat exchanger, the defrosting of the outdoor heat exchanger can be achieved without hindrance while maintaining heating of a vehicle interior. A refrigerant discharged from a compressor 2 radiates heat in a radiator 4 and the refrigerant by which heat has been radiated is decompressed and then absorbs heat in an outdoor heat exchanger 7 to heat the vehicle interior. The air conditioning device for vehicle includes an injection circuit 40 which distributes a part of the refrigerant flowing out from the radiator 4 to return the part to the compressor 2. When a controller 32 passes the high-temperature refrigerant through the outdoor heat exchanger 7 to perform defrosting, the controller operates the injection circuit 40 to return the refrigerant to the compressor 2.