It is to provide an agent for preventing and treating skin aging, or an agent for treating skin scar that can exert a sufficient effect. An agent for preventing and treating skin aging comprising bFGF for treating aging of the skin that is administered intradermally or subcutaneously, or an agent for treating skin scar comprising bFGF for treating scar of skin that is administered intradermally or subcutaneously is utilized. Preferred examples of aging of skin include skin wrinkle, pigmented spot, sagging skin, rough skin, skin thinning, decrease of skin viscoelasticity, etc., and preferred examples of scar include keloid, hypertrophic scar, scar contracture, etc.
