A photocatalyst composition which comprises (A) modified photocatalyst particles, the modified photocatalyst particles (A) being prepared by subjecting particles of a photocatalyst to a modification treatment with at least one modifier compound selected from the group consisting of different compounds each of which independently comprises at least one structural unit selected from the group consisting of a triorganosilane unit, a monooxydiorganosilane unit and a dioxyorganosilane unit; and (B) a binder component comprising a phenyl group-containing silicone optionally containing an alkyl group. A film formed using the above-mentioned photocatalyst composition, a functional composite comprising a substrate and the above-mentioned film formed on the substrate, and a shaped article produced by shaping the above-mentioned photocatalyst composition.