To provide a zinc oxide fine particle which has a restraint substrate- degradation due to its catalytic activity without losing the UV shielding ability of zinc oxide, and has an excellent dispersion stability in aqueous media due to its restraint zinc-ion-elution and its slurry, and to provide a polymer composi tion, a molded item having an optical function and a structural body having an optical function using them.

This silica-coated zinc oxide fine particle which has a surface coated with a specific dense silica thin film, an average primary particle size of 5-200 nm and a silica thin film having a thickness of 0.5-100 nm. The aqueous slurry is obtained by dispersing this zinc oxide fine particle.