To improve the CO2-reforming performance of TiO2 photocatalyst, various metals were supported by means of photodeposition on coated TiO2 film prepared by sol-gel and dip-coating method, and CO2-reforming performance of such coated TiO2 film was evaluated. When Pd was supported on the surface of coated TiO2 film on Cu tube, the effect of the supported metal was not fully realized, because the coated TiO2 film was separated from the Cu tube by embrittlement in the process of supporting the metal. When the coated TiO2 film was prepared by dissolving TiO2 powder with the supported metal in TiO2 sol solution, the CO2-reforming performance of coated TiO2 film with Pd supported on TiO2 powder was the highest among coated TiO2 films with Cu, Pd or Pt supported on TiO2 powder. The performance of reforming a gaseous mixture of CO2 and H2O into CO and hydrocarbon was promoted by decreasing firing time from 420 s to 180 s irrespective of supported metal type. With the aid of supported metal, the concentration of produced CO, the intermediate in the production of CH4, increased with the concentration of produced CH4, resulting in improved CO2-reforming performance of coated TiO2 film.