Deposition of ultrafine particle of silver on titanium dioxide (TiO2) significantly improved the photocatalytic activity for degradation of gaseous sulfur compounds, such as hydrogen sulfide (H2S) and methylmercaptan (CH3SH). The silver-deposited photocatalytic filter (Ag-PCF) was prepared by coating TiO2 powder on the porous ceramics substrate and successively depositing nano-sized silver particles on TiO2 by means of photodeposition method. The photocatalytic degradation rates of hydrogen sulfide and methylmercaptan by Ag-PCF were 7 times and 14 times larger, respectively, than those by conventional photocatalytic filter. The sulfur atom of hydrogen sulfide was oxidized into sulfate ion, which was accumulated on the filter. However, the degradation rate did not decline in the experimental period. The deposited silver seems to act as a co-catalyst that enhances the photocatalytic oxidation of sulfur compounds. (c) 2004 Elsevier B.V. All rights reserved.