PURPOSE: To provide a fiber-reinforced composite material providing excellent strength characteristics oxidation resistance and fracture toughness even at high temp. and highly suitable to a heat insulation material, etc., of a superhigh- speed flying body.

CONSTITUTION: This material is a silicon carbide fiber reinforced composite material reinforced its matrix consisting of silicon carbide or silicon nitride at both-surface parts or single-surface part with silicon carbide fibers, and the inner base part sandwitched with the both-surface parts or the base part including the single-surface part consisting of the carbon fiber reinforced composite material reinforced its matrix consisting of carbon, silicon carbide, silicon nitride or boron carbide with carbon fibers. This fiber-reinforced functionally gradient material is characterized in that the carbon fiber content ratio at the inner base part or at the base part continuously decreases from the center part to the boundary part of the both-surface part or single-surface part.