To obtain the subject composition excellent in skin-beautifying effect by including an extract of a plant of the family Betulaceae.

This composition comprises an extract of a plant belonging to the genus platyphylla of the family Betulaceae and/or a plant belonging to the genus Alnus of the family Betulaceae, a polyglycerol fatty acid ester, a water-soluble polymer and semisolid or solid ester oil. The plant extract is obtained by extracting, preferably bark of the plant with a solvent such as ethanol and contains the extract in an amount of 0.001-10wt.%. Preventing effect of the extract of a plant of the family Betulaceae on skin aging, is synergistically enhanced and moisture-retaining effect and skin beautifying effect are improved. The composition is prepared in the form of cream, emulsion, etc.