By pouring a solution containing hydrolyzable tin and antimony salts into an aqueous dispersion of titanium oxide particles and mixing, the salts are caused to hydrolyze, whereby a uniform and strongly adherent coating layer of antimony-containing tin oxide is formed on the surface of each particle of the titanium oxide. The coated powder thus obtained is non-hygroscopic and non-toxic and exhibits stable electroconductivity. Furthermore, since it can possess excellent whiteness, it is suitable for forming the electroconductive layers of electro-thermosensitive papers and electrostatic recording papers, for use as the antistatic agent of resins, and for other uses.