A vehicle air conditioning apparatus comprising: an outside air inlet through which outside air is introduced from outside of a passenger compartment; an inside air inlet through which inside air is introduced from inside of the passenger compartment; a heat exchanger that exchanges heat between inside air introduced through the inside air inlet and outside air introduced through the outside air inlet; a blower fan that blows outside air which has been subjected to heat exchange by the heat exchanger, or outside air introduced through the outside air inlet, or inside air introduced through the inside air inlet; an evaporator that cools outside air or inside air blown by the blower fan; and a condenser that heats the outside air or inside air cooled by the evaporator and sends the heated outside air or inside air toward the inside of the passenger compartment, wherein: a first flow passage is formed through which outside air or inside air flows in the order of the blower fan, the evaporator, the condenser, and the inside of the passenger compartment; a second flow passage is formed which is separated from the first flow passage, and through which inside air flows in the order of the inside air inlet, the heat exchanger, and the outside of the passenger compartment; and the heat exchanger exchanges heat between outside air introduced through the outside air inlet by suction power of the blower fan, and inside air introduced into the second passage after passing through the first passage and the inside of the passenger compartment by a blowing force of the blower fan, characterized in that the blower fan discharges inside air which has been subjected to heat exchange to the outside of the passenger compartment by using a drain hose provided for discharging drain water to the outside of the passenger compartment, the drain water being generated when outside air is cooled by the evaporator. an outside air inlet through which outside air is introduced from outside of a passenger compartment; an inside air inlet through which inside air is introduced from inside of the passenger compartment; a heat exchanger that exchanges heat between inside air introduced through the inside air inlet and outside air introduced through the outside air inlet; a blower fan that blows outside air which has been subjected to heat exchange by the heat exchanger, or outside air introduced through the outside air inlet, or inside air introduced through the inside air inlet; an evaporator that cools outside air or inside air blown by the blower fan; and a condenser that heats the outside air or inside air cooled by the evaporator and sends the heated outside air or inside air toward the inside of the passenger compartment, wherein: a first flow passage is formed through which outside air or inside air flows in the order of the blower fan, the evaporator, the condenser, and the inside of the passenger compartment; a second flow passage is formed which is separated from the first flow passage, and through which inside air flows in the order of the inside air inlet, the heat exchanger, and the outside of the passenger compartment; and the heat exchanger exchanges heat between outside air introduced through the outside air inlet by suction power of the blower fan, and inside air introduced into the second passage after passing through the first passage and the inside of the passenger compartment by a blowing force of the blower fan, characterized in that a first flow passage is formed through which outside air or inside air flows in the order of the blower fan, the evaporator, the condenser, and the inside of the passenger compartment; a second flow passage is formed which is separated from the first flow passage, and through which inside air flows in the order of the inside air inlet, the heat exchanger, and the outside of the passenger compartment; and the heat exchanger exchanges heat between outside air introduced through the outside air inlet by suction power of the blower fan, and inside air introduced into the second passage after passing through the first passage and the inside of the passenger compartment by a blowing force of the blower fan, characterized in that