Provided is a novel compound which has excellent ultraviolet-absorbing function (especially UVA absorbing function) and excellent hydrophilicity. A benzylidene azolidine derivative of the present invention or a salt thereof is characterized by being a benzylidene azolidine derivative represented by specif ic structural formula (I) or a salt thereof. (In structural formula (I), n represents an integer of 1-5； A1 represents O, S or N-A4； and each of A2, A3 and A4 independently represents a hydrogen atom, an alkyl group which may be substituted by a hydroxyl group and has 1-8 carbon atoms, or the like (provided that at least one of A2, A3 and A4 contains one or more hydroxyl groups). In this connection, when n is an integer of 2-5, the plurality of A3O- moieties may be the same as or different from each other.)
