An air conditioner comprises a water distributor having an opening on its bottom plate, dams around the opening and inverted U-shaped members with a small space formed between the inverted U-shaped plates and the dams so that water in the distributor is guided by a capillary action and distributed to an indoor heat exchanger. A reservoir is disposed to a pipe system between a pump and the indoor heat exchanger so that drain water in the outdoor drain pan is directed to the indoor heat exchanger through the reservoir. The reservoir has a tube which permits excessive water to spill over an opening of the tube to return to the outdoor drain pan through a returning conduit pipe.