The present invention addresses the problem of providing a novel skin collagen production-promoting agent for promoting the biosynthesis of skin collagen, which is capable of preventing dry skin, rough skin, wrinkles and sagging, and can also be used as a food material without any safety problems. The present invention also addresses the problem of providing foods, drinks and cosmetic materials containing the skin collagen production-promoting agent. The skin collagen production-promoting agent uses milk protein fractions having the following characteristics (a) to (c) as the active ingredient. (a) The milk protein fractions are derived from milk. (b) The fractions, obtained by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), contain proteins with molecular masses ranging from 6,000 to 150,000 daltons. (c) The constituent amino acid composition contains 12 to 14 wt % basic amino acids, and the ratio of basic amino acids/acidic amino acids ranges from 0.5 to 0.7.
