PURPOSE: To completely discharge out of the room drain water such as dew or the like generated from an evaporator when it overflows by forming a water receiving pan into a dual structure by setting the height of the inside water receiving pan lower than that of the outside water receiving pan.

CONSTITUTION: A water receiving device 8 has a dual structure comprising an internal water receiving pan 14 made of a highly heat-insulating material and an external water receiving pan 13 covering the entire outside of the internal water receiving pan 13. Since the internal water receiving pan 14 is lower than the external water receiving pan 13, drain water such as dew which has overflowed therefrom flows through a clearance formed between the internal water receiving pan 14 and the external water receiving pan 13 and is discharged via a drain port 15.