PURPOSE: To improve collapsibility easily collapsing even in the case of using to casting of metal having low melting point by adding the specific urea resin to phenol resin.

CONSTITUTION: The solid urea resin is added to the phenol resin at 10W40%. By this method, as the collapsibility is extremely good and it comes to be possible to easily collapse even at low temp., even in the case of using to the casting of the metal having low melting point, such as Al, removal of molding sand from the casting after casting and recovery of the molding sand are simply executed. That is, troublesome posttreatment process, such as heating at high temp., for long time, give of intensive shock, is simplified and the casting opera tion is made efficient and the casting cost is reduced.