The present invention includes the steps to make the hydrolysis solution by the addition of Si-based alkoxide in water; Step by mixing the primary dispersion of the hydrolysis solution and the fine silica powder for manufacturing a silica slurry; Step drying the silica slurry, by mechanical grinding and calcining for producing a silica of granule; Step to disperse the sintered silica granules to obtain a secondary dispersion liquid of the silica slurry; F to the silica ^{dispersion-phase} after the addition of salt containing the ion milling for preparing a silica sol; The step of gelling in a mold by injecting the silica sol in a mold; Removing the formed article from the mold to obtain a gelled wet gel; Drying the wet gel; Step of first heat treatment of the dried gel at 300 to 600 ℃; Secondary heat treatment step of the heat treatment the resultant at 500 to 1000 ℃; And it provides a method for producing silica glass comprising the step of sintering under the second heat treatment results in a vacuum atmosphere. Silica glass, alkoxide, vacuum sintering, sol-gel, silica fume served