Disclosed is an anti-aging composition for external use on skin, which includes low-molecular weight hyaluronic acids, high-molecular weight hyaluronic acids and polysaccharides extracted from root bark of Ulmus davidiana, as active ingredients. The composition including the low-molecular weight hyaluronic acids, high-molecular weight hyaluronic acids and polysaccharides extracted from root bark of Ulmus davidiana, in a predetermined ratio, shows significantly improved skin-moisturizing, skin elasticity-enhancing and inflammation-alleviating effects, as compared to a composition using one of the above alone. Therefore, the composition may be widely used as a pharmaceutical or cosmetic anti-aging composition.