Further, there is a process for producing a F-containing TiO2???SiO2 glass body, wherein by a direct method, compounds containing F are used as the Si precursor and the Ti precursor as the glass-forming materials, or the Si precursor and the Ti precursor are hydrolyzed and oxidized in an oxyhydrogen flame of from 1,800 to 2,000??? C. in a F-containing atmosphere.