It is one of the objects of the present disclosure to provide a water-based dispersion prepare a stable O/W product having an ultralight shielding effect, and to provide a cosmetic having a good feeling and a strong water repellency for sweat and water, by blending the water-based dispersion to a cosmetic.A water-based dispersion which contains an inorganic powder microfine particle subjected to a hydrophobic organic surface treatment, a polyhydric alcohol, water, and a nonionic surfactant,wherein the nonionic surfactant is a compound which can be dissolved transparently or slightly muddy in 1,3-butylene glycol (20 wt % concentration, 35° C.), and an amount of the inorganic powder microfine particle is 30 wt % or more.