A titanyl sulfate solution or a titanium tetrachloride solution is neutralized with an alkali to form orthotitanic acid, to which hydrochloric acid is added such as to adjust the TiO.sub.2 concentration to 80-140 g/L and the HCl concentration to 90-150 g/L and a synthesis reaction is performed at a temperature of 25-60.degree. C. to produce titanium oxide particles in which needles aggregate and/or bind together to yield fan-shaped particles.