To provide an air conditioner for preventing water leakage by preventing dripping to the outside of drain pans of condensation water sticking to a heat exchanger in the air conditioner arranged in the ceiling.

This air conditioner has the heat exchanger 4 slantingly arranged inside, an air blower 6 for blowing air to this heat exchanger 4, the first drain pan 11 arranged in a lower end part of the heat exchanger 4 and receiving the condensation water from the heat exchanger 4 and the second drain pan 7 arranged so as to cover an under surface of the heat exchanger 4, receiving the condensation water of a heat exchanger 4 upper part and draining this condensation water to the first drain pan 11, and is arranged in the ceiling in a room. A sheet plate 24 is arranged so as to cover the side of the heat exchanger 4 by being raised upward from a side plate 9 of the second drain pan 7.