PURPOSE: To increase water retention characteristics of a drain device to be mounted slantingly on a ceiling part of a storage chamber in a refrigerator.

CONSTITUTION: A drain pan 20 whose water retention characteristics are increased by forming a plurality of grooves 23 having a polygonal shape, that is substantially square or more in cross-section, on the lower surface of a drain plate 21 and to which hydrophilicity is imparted by spraying an abrasive material to the drain plate to form recesses and protrusions, flaws and the like thereon, is mounted slantingly on a ceiling at the upper part of a storage chamber in a refrigerator in such a manner that the direction of the grooves 23 is directed toward a lower direction.