As a visible-light-responsive photocatalytic-titanium-oxide-particulate dispersion liquid that can achieve a high visible light activity and is of a type different from the related art, the present invention provides a visible-light-responsive photocatalytic-titanium-oxide-particulate dispersion liquid in which two types of titanium oxide particulates are dispersed in an aqueous dispersion medium. The two types of titanium oxide particulates are first titanium oxide particulates, in which a tin component and a transition metal component (but excluding an iron-group component) for enhancing visible light responsiveness are dissolved, and second titanium oxide particulates, in which an iron-group component is dissolved. When a photocatalytic film formed by using this dispersion liquid is used, a high decomposition activity is achieved even in a case where a decomposition substrate has low concentration, which was previously difficult under visible light conditions.