A fiber-composite material (7) is comprised of a yarn aggregate (6) in which yam (2A, 2B) including at least a bundle (3) of carbon fiber and a carbon component other than carbon fiber is three-dimensionally combined and integrally formed without separation from each other; and a matrix made of Si—SiC-based materials (4A, 4B, 5A, 5B) filled between the yarn (2A, 2B) adjacent to each other within the yarn aggregate (6). A method of preparing fiber-composite material is comprised of the steps of: producing bundles (3) of carbon fiber by impregnating a component of powdery carbon into the bundles (3) of carbon fiber, which eventually forms a matrix shape; forming a plastic coat around the bundles (3) of carbon fiber to obtain an intermediate material; molding the intermediate material to obtain a molded product by making the intermediate material into a yarn-shape and laminating a predetermined amount of the material, or burning the molded product to obtain a burned product; holding the molded product or the burned product and Si, at 1100 to 1400° C. in an atmosphere of inert gas; and heating the molded product or the burned product and Si to a temperature from 1450 to 2500° C., to thereby impregnate Si—SiC-based material into the inside of pores of the molded product or the burned product. A light and strong composite material is provided, which has excellent shock resistance, corrosion resistance in a strong oxidation and corrosion environments, creep resistance, spalling resistance, wear resistance, a low friction coefficient and a self-restorative ability by which a defect is healed.