Researchers have patented a production process that comprises a preform formation step of forming a fiber preform made of silicon carbide short fibers having heat resistance of 1000�C or greater; a sol-gel preparation step of preparing a sol-gel solution containing a heat resistant compound having heat resistance of 1000�C or greater; an impregnation-drying-calcination step of impregnating the fiber preform with the sol-gel solution, followed by drying and calcining; and a crystallization step of crystallizing the fiber preform after impregnation, drying and calcination.