To provide a method for manufacturing high-purity zirconium hydroxide by extremely efficiently removing/reducing Fe content when manufacturing the zirconium hydroxide through neutralization using zirconium oxychloride as a starting material, and to provide zirconium oxide having an extremely high lightness and whiteness and its sintered compact through the same.

In a method, the zirconium oxide is manufactured by adding an alkali source to an aqueous zirconium oxychloride solution to obtain a hydroxide and drying and calcining the obtained hydroxide. In this method, a zirconium oxide powder is manufactured by adding the alkali source to the aqueous zirconium hydroxide solution to adjust the pH to 1.5-2.5 and separating zirconium hydroxide precipitate at this pH. In the zirconium hydroxide powder, values L*, a* and b* of the L*a*b* color system, designated in JIS Z 8729, satisfy the relations: L*≥95, -1<a*<1 and -5<b*<5, respectively.