By coating the surface of a powder comprising a silicone resin and/or an organic powder with a specific hydrophilizing agent, such powder is hydrophilized. The hydrophilizing agent includes water-soluble polyoxyalkylene glycol derivatives. The organic powder is at least one selected from PMMA, nylon, polyester, polystyrene, cellulose, silicone elastomer powder, silicone rubber powder, benzoguanamine, styrenedivinylbenzene pinhole polymer, ethylene tetrafluoride, polyethylene powder, polypropylene powder, polyurethane powder, silk powder, metal soap powder, starch powder, N-acylated lysine, an organic pigment, and a composite of at least one of these organic powders described above with a metal oxide and/or a metal hydroxide. Such coated (treated) powder has extremely great dispersibility (ease of dispersion) and very good dispersion stability (long-term dispersion stability with lapse of time) in aqueous dispersion media, particularly under acidic and alkaline conditions, specifically at pH 3 through 13. Using the surface-treated powder, additionally, a dispersion with good dispersibility (ease of dispersion) and great dispersion stability, preferably for cosmetics can be provided. The use of the surface-treated powder, or the use of the dispersion can provide further a cosmetic excellent in dispersibility and dispersion stability and further in re-dispersibility and dispersion stability with lapse of time and smooth feeling as compared to the related art when selecting aqueous cosmetic as an agent form.
