The present invention has an object to provide an external dermal agent with a sustainable anti-wrinkle action, which has both the action of enhancing the proliferation and differentiation of keratinocytes in the skin and the action of enhancing the collagen production in the skin, and which assists the maintenance and the improvement of tissue structures and physiological functions of the epidermis and the dermis, whereby providing a remarkable skin improvement effect. The present invention solves the above object by providing an external dermal agent containing α-D-glucopyranosyl-(1→3′)-adenosine and/or α-D-glucopyranosyl-(1→5′)-adenosine as an effective ingredient(s).