Abstract: The present invention relates to a unitary heat exchanger for an air conditioner which is capable of minimizing the size, weight, and the power consumption thereof, and improving the thermal efficiency. The unitary heat exchanger comprises an air intake member for introducing the room air, and a combustion furnace for firing a fuel with the air introduced through the air intake member to generate a hot combustion gas. A heat exchanger is disposed in line with the furnace for passing the hot combustion gas from the combustion furnace therethrough and heating fresh room air supplied by a blower. An air exhaust member discharges the hot combustion gas from the heat exchange means.