Photocatalytic properties of titanium dioxide layer deposited on silica glass (SG) including silver nanoparticles at a shallow depth were studied from an aspect of utilization of surface plasmon resonance (SPR) by nanoparticles. In order to adjust resonant photon energy of surface plasmon to the activation energies of 3.0 and 3.2 eV depending on crystallinity of TiO₂, Ag nanoparticles were formed in SG at a shallow depth by silver negative-ion implantation and post annealing. Then, TiO₂ layer was formed on it at temperatures of 200 and 500°C by rf magnetron sputter deposition. Ag nanoparticles were confirmed from optical absorption by the SPR at 3.0-3.1 eV. The deposited TiO₂ film at substrate temperature of 200°C was found to have anatase-type nano-crystals from results of XRD and optically measured bandgap. Photocatalytic properties of TiO₂ layer deposited on Ag-implanted silica glass at 200°C were evaluated by decolorization of methylene blue solution and compared with that of the TiO₂ film deposited on unimplanted SG at the same conditions. As a result, the TiO₂ layers deposited on Ag-implanted SG after annealing at 700°C were showed an enhancement in photocatalysis of factor 3.26.