PURPOSE: To accomplish removal binder in a relatively short time and to remove a binder by using an inexpensive heat-resistant powder capable of being repeatedly utilized when the injection-molded body is embedded in the powder, the molded body is indirectly heated from the surface of coating powder to heat and decompose the org. binder, and the decomposed binder is removed outside from between the grains of the powder.

CONSTITUTION: An injection-molding kneaded material consisting of a raw metal powder and an org. binder is injection-molded, and the molded body is embedded in a heat-resistant powder and then heat-treated to remove the binder from the molded body. In this case, the heat-resistant powder is formed with calcium carbonate, and the whole calcium carbonate powder contains 5-40vol.% of the calcium carbonate powder having a smaller average grain diameter than the raw metal powder.