The invention provides an air conditioning unit. In a unit case having the suction inlet port and the suction outlet port, a heat exchanger for dehumidifying air and a heat exchanger for heating air are arranged in an air passage from a suction inlet port to a suction outlet port, and a heat exchange area is partitioned into a suction-inlet-side heat exchange area and a suction-outlet-side heat exchange area by the heat exchanger for dehumidifying air and the heat exchanger for heating air, wherein the water generated in the heat exchange area is discharged to a bottom portion of the heat exchange area through a drainage passage provided with a projection or a narrowed portion as obstruction portions for catching a foreign matter such as lint so as not to flow onward.