Abstract: A first PTC heater and a second PTC heater are provided at the downstream side of a heater core that uses engine cooling water for its heat source, and the second PTC heater is positioned at a foot outlet. Under conditions that require the use of the PTC heaters, power is supplied to all the PTC heaters if the discharge mode is set to a FOOT mode or a DEF/FOOT mode, whereas power is supplied only to the first PTC heater if the discharge mode is set to a DEFROST mode. In an air conditioning control apparatus for vehicles provided with a heater core and PTC heaters, warm air at appropriate temperatures can be supplied through both the foot outlet and the defrost outlet during an initial stage of heating in which the temperature of the engine cooling water is low. In addition, since no power is supplied to the second PTC heater unless the foot outlet is open, energy resources are saved.