HTaWO 6 /(Pt, TiO 2 ) nanocomposite was synthesized by successive intercalation reactions of HTaWO 6 with Pt(NH 3 ) 4 2 + , C 3 H 7 NH 2 /heptane mixed solution and TiO 2 acidic sol, followed by UV irradiation. The height of TiO 2 and Pt pillar is less than 0.51 nm. The host HTaWO 6 was white and possessed band gap energy of 3.11 eV, whereas the HTaWO 6 /(Pt, TiO 2 ) nanocomposite was yellow and showed broad reflection over 400-600 nm together with that corresponding to the host layer, and possessed both excellent hydrogen evolution and nitrogen monoxide destruction photocatalytic activities even under visible light irradiation (λ>510 nm). The HTaWO 6 /(Pt, TiO 2 ) possessed higher photocatalytic activity than those of undoped HTaWO 6 , commercial titania powder (Degussa P-25), fibrous titania and Pt-doped fibrous titania.