PROBLEM TO BE SOLVED: To provide an oil-in-water type mascara foundation which improves the usability and functional characteristics of mascara of an excellent effect of making the eyelash seem thick and an excellent effect uniformly and neatly applying mascara in applying mascara to the eyelash several times in order to obtain an effect of separating the eyelash into an individual eyelash without sticking in a bundle among eyelashes and a cosmetic benefit of making the eyes conspicuous by previously applying the mascara foundation to the eyelash.SOLUTION: The oil-in-water type mascara foundation comprises component (a) of spherical silicone particles having fine protrusions over the entire particle surface, component (b) of an oil-soluble resin, and component (c) of an alkyl acrylate copolymer emulsion.