The present invention intends to provide a gypsum-based embedding material composition for casting, the composition being useful as a rapid-heating type gypsum-based embedding material making it possible to provide a product with which leaving time is made short, which has never been realized in conventional products, and also intends to provide a method for producing the same. A gypsum-based embedding material composition for casting, the composition being a gypsum-based powdery embedding material composition for casting to be used for a rapid-heating type embedding material, the gypsum-based powdery embedding material composition being such that a set product is put into a high-temperature furnace, the set product obtained by adding a malaxation liquid into the composition to perform malaxation and then setting a resultant mixture, wherein the gypsum-based embedding material composition for casting contains as main components calcined gypsum, quartz, and cristobalite, and contains at least one co-pulverized material selected from a co-pulverized material of calcined gypsum and quartz, a co-pulverized material of calcined gypsum and cristobalite, or a co-pulverized material of calcined gypsum, quartz, and cristobalite, and a powdery moisture-retaining component or a liquid moisture-retaining component having a low water content, the composition having an average particle diameter of 30 μm or less, and a method for producing the same.
