Disclosed is an oily dispersion of an inorganic microparticle oxide powder. The oily dispersion has excellent feel, uses highly safe ester oil, liquid paraffin, and other hydrocarbon oils, has excellent compatibility with other cosmetic material components, and moreover has a high solid concentration, a low viscosity, and an excellent stability over time. Further disclosed is a cosmetic material with high transparency and high SPF value using the oily dispersion. The oily dispersion is composed of two elements: a dispersion medium, and a surface-treated inorganic microparticle oxide powder. The oily dispersion is characterized by the dispersion medium being an oil； the surface-treated inorganic microparticle oxide powder being a surface-treated powder wherein the proportion to a base material powder of either a branched fatty acid having isostearic acid as a primary constituent element or a metal salt having isostearic acid as a primary constituent element is 1-30 mass %； the solid concentration of surface-treated inorganic microparticle oxide powder when forming the oily dispersion being 25 mass %； and the viscosity at 25ºC being no more than 2000 mPa·s.
