Abstract: A photocatalytic powder for environmental clarification, comprising finely divided titanium dioxide particles having a coating of porous calcium phosphate formed on at least part of the surface of each titanium dioxide particle, wherein an anionic surface active agent is present at least on the interface between said coating of porous calcium phosphate and the titanium dioxide particle. This photocatalytic powder is produced by dispersing finely divided titanium dioxide particles in an aqueous slurry containing an anionic surface active agent, and then forming a coating of porous calcium phosphate on at least part of the surface of each titanium dioxide particle. This photocatalytic powder is used, for example, by supporting it in an organic polymer shaped article.