The present invention relates to an inhibitor for the biosynthesis of gelatinase comprising ginsenoside F1 (20-O-.beta.-D-glucopyranosyl-20(S)-protopanaxatriol) or compound K (20-0-.beta.-D-glucopyranosyl-20(S)-protopanaxadiol), which is a chief metabolite of ginseng saponin, as an active ingredient; and a cosmetic/medical composition for the prevention of skin-aging comprising the same which is superior in inhibiting the decomposition of epidermal-dermal junction and also in accelerating the generation thereof.