A vehicle air conditioner is controlled so a target control value of a
pressure control valve controlling tilt angle of a swash-plate of a
swash-plate type variable capacity compressor is variably controlled
according to temperature deviation between target evaporator temperature
and actual evaporator temperature, thereby controlling the compressor
discharge capacity. Target heat discharge quantity is calculated. Target
heat discharge quantity is calculated for high thermal load control or
low thermal load control. The control value of the pressure control valve
is compulsively controlled. Then the control value is normally
controlled. The actual evaporator temperature can reach the target
evaporator temperature at an initial operating stage, and temperature
stability is secured.