The present invention provides an oil-based humectant which is characterized by being composed of an esterified product of a component A and a component B, or an esterified product of a component A, a component B and a component C, and which is also characterized in that: the esterified product has a hydroxyl value of 0-180 mgKOH/g； and the mass ratio of the fatty acid residues derived from the component B to the fatty acid residues derived from the component C in the fatty acid residues constituting the esterified product of the component A, the component B and the component C is from 99.9:0.1 to 25:75. The present invention also provides a composition for external application to the skin, which contains this oil-based humectant.Component A: a polyglycerol which has an average degree of polymerization of 2-10 as calculated from the hydroxyl valueComponent B: one or more fatty acids which are selected from among linear saturated fatty acids having 6-10 carbon atomsComponent C: one or more fatty acids which are selected from among fatty acids having 6-28 carbon atoms (excluding the component B)L'invention fournit un agent hydratant huileux et une composition pour la peau à usage externe contenant celui-ci. L'agent hydratant huileux de l'invention est caractéristique en ce qu'il est constitué d'un composé ester à base d'un composant (A) et d'un composant (B) ou d'un composé ester à base d'un composant (A), d'un composant (B) et d'un composant (C). En outre, l'indice d'hydroxyle dudit composé ester est compris entre ０ et １８０ｍｇＫＯＨ／ｇ. Enfin, le rapport de masse d'un résidu d'acide gras dérivé du composant (B) et d'un résidu d'acide gras dérivé du composant (C) parmi les résidus d'acide gras configurant ledit composé ester à base d'un composant (A), d'un composant (B) et d'un composant (C), est compris entre ９９,９：０,１ et ２５：７５. Composant (A) : polyglycérine de degré moyen de polymérisation calculé à partir de l'indice d'hydroxyle compris entre 2 et 10 ； composant (B)
