TiO₂ photo-catalyst incorporated into three-dimensional porous ceramics of Si/SiC with similar structure as that of polyurethane sponge ensured efficient decomposition of NO_X not only under the irradiation with UV rays but also under the illumination with fluorescent lamp. The 3D photo-catalyst filter was characterized by finer bridge elements, providing high transmittance, enhanced contact probability with pollutant and lower pressure loss. These properties are ideal for a carrier of photo-catalyst.