A method for manufacturing a microparticulate anatase or rutile titanium oxide dispersion from a peroxotitanic acid solution optionally containing tin, wherein the method for manufacturing an anatase or rutile titanium oxide dispersion is characterized in that the peroxotitanic acid solution is fed continuously to a flow reactor and subjected to hydrothermal treatment at 150 to 250° C. and 0.5 to 10 MPa. The invention makes it possible to provide a method for manufacturing a microparticulate anatase or rutile titanium oxide dispersion having excellent stability in regard to the titanium oxide microparticles and enabling a high-transparency photocatalytic thin film to be produced, and to provide a member having a photocatalytic thin film formed on the surface using this dispersion.