There is provided a method for efficiently producing an anatase-type titanium oxide sol in an extremely advantageous dispersion state. The method comprises mixing a titanium alkoxide, an organic acid, and a quaternary ammonium hydroxide with water in a molar ratio of the organic acid of 0.4 to 4.0 relative to 1 mol of a titanium atom of the titanium alkoxide and in a molar ratio of the quaternary ammonium hydroxide of 0.8 to 1.9 relative to 1 mol of the organic acid to prepare an aqueous mixed solution having a concentration in terms of TiO2 of 0.5 to 10% by mass heating the aqueous mixed solution to 50 to 100° C. to remove an alcohol and subjecting the resulting titanium-containing aqueous solution to a hydrothermal treatment at 110 to 170° C.
