A cosmetic substrate composed of a silylated amino acid/silane compound copolymer obtained by poly-condensing at least one silylated amino acid having a specific chemical structure and at least one silane compound having a specific chemical structure, wherein the reaction molar ratio of silylated amino acid:silane compound is in the range of 1:5 to 1:150, and a cosmetic containing 0.01% by mass or more and 20% by mass or less of the cosmetic substrate are provided.
