There is disclosed a vehicle air conditioner which is capable of enlarging an effective range of a dehumidifying and heating mode to environmental conditions and smoothly dehumidifying and heating a vehicle interior. A vehicle air conditioner 1 executes a dehumidifying and heating mode in which a controller lets a refrigerant discharged from a compressor 2 radiate heat in a radiator 4, and decompresses the refrigerant by which heat has been radiated and then lets the refrigerant absorb heat in a heat absorber 9 and an outdoor heat exchanger 7, the controller decreases an outdoor blower voltage FANVout of an outdoor blower 15 and decreases an air volume into the outdoor blower 15 in a case where a temperature Te of the heat absorber 9 is high even when the controller adjusts a valve position of an outdoor expansion valve 6 into a lower limit of controlling in a situation in which a temperature TCI of the radiator 4 is satisfactory.

A vehicle control device includes: a controller configured to adjust a temperature of an evaporator constituting an air conditioning system of the vehicle to a target temperature; the controller being configured to automatically stop an engine when a predetermined engine automatic stop condition is satisfied; the controller being configured to automatically start the engine when at least the temperature of the evaporator reaches a predetermined temperature or higher during automatic stop of the engine, and the predetermined temperature being higher than the target temperature; and the controller being configured to set the target temperature of the evaporator to be lower when a vehicle speed is low than that when the vehicle speed is high.

A vehicle-mounted temperature adjustment device included in a vehicle air-conditioning device includes a low-water-temperature circuit through which low-water-temperature cooling water circulates. In addition, the vehicle-mounted temperature adjustment device has a compressor, a condenser, a subcooling condenser, an expansion valve, which is one example of a first expansion unit, an expansion valve, which is one example of a second expansion unit, and an evaporator and refrigerant-water heat exchanger, and includes a refrigeration circuit that performs temperature adjustment of a temperature-adjustment target. The low-water-temperature circuit has a sub-radiator that releases heat of the low-water-temperature cooling water that has been subjected to heat exchange with refrigerant at the subcooling condenser.