An air conditioner comprises an outdoor heat exchanger having a plate fin whose surface is treated to have water-sliding properties and water repellency and a drain pan arranged under the outdoor heat exchanger. There is a gap throughout between the lower end portion of the outdoor heat exchanger and the upper surface of the drain pan. Water droplets condensed when the outdoor heat exchanger operates as an evaporator fall on the drain pan from the lower end portion of the plate fin. Since the plate fin and the drain pan are not in contact with each other, there is no such case that ice adheres to the contact portion and frost develops therefrom.