To provide a method for producing superfine metal oxide particles capable of effectively generating superfine particles in the case of using large sized particles as a raw material, and without using a difficult-to-handle raw material by introducing specific dried gel particles into a high temperature plasma-atmosphere gas.

The method for producing superfine metal oxide particles is to use a compound which can be converted to a gel by hydrolysis, e.g. one or more kinds of compound of Si, Zn, Ti, niobium and tin, but especially a silicon alkoxide such as tetramethoxysilane and tetraethoxysilane is easily hydrolyzed to give a gel excellent in characteristics. The gelation by hydrolysis is performed by using 1mol silicon alkoxide with 2-10mols of water at pH2-8 during the gelation, and since the gelation reaction is so rapid in the acidic region, the reaction is controlled by adding an alcohol. The reaction temperature is 20-80°C and the temperature is kept at the reaction temperature for several hrs. after gelation until its completion, and gel particles having 50-500μm particle diameter and 0.5-20wt.% water content are obtained by crushing the obtained gel and sieving. The obtained particles are introduced into an electrode less-type thermal plasma at ≥2000°C.