[Object] Provided are a drug, a cosmetic, and a supplement containing a food ingredient or nutrient with safety and experience having been eaten for a long time and that shows a collagen enhancing activity. [Solution] The skin collagen enhancing agent of the present invention contains menaquinone-7 as an active ingredient. The skin collagen enhancing agent of the present invention is administered percutaneously or orally and is provided as a drug, a cosmetic, or a supplement.