PROBLEM TO BE SOLVED: To provide a zirconia sintered boy having high light transmissivity and high strength and excellent in aesthetic property and designability.SOLUTION: There is provided a zirconia sintered body containing crystal particles having a cubic domain and a tetragonal domain, solid dissolving a stabilizer and lanthanum, containing at least one of lanthanoid other than lanthanum or a transition metal and having average crystalline diameter calculated from half width of a peak of 2θ=30±2° in a powder X ray diffraction pattern with CuKα as a radiation source of over 255 nm.SELECTED DRAWING: Figure 2【課題】高い透光性及び高い強度を兼備し、なおかつ審美性及び意匠性にも優れたジルコニア焼結体の提供。【解決手段】立方晶ドメイン及び正方晶ドメインを有する結晶粒子を含み、安定化剤及びランタンを固溶し、なおかつ、ランタン以外のランタノイド又は遷移金属の少なくともいずれかを含有し、ＣｕＫαを線源とする粉末Ｘ線回折パターンにおける２θ＝３０±２°の半値幅から算出される平均結晶子径が２５５ｎｍ以下であるジルコニア焼結体。【選択図】図２
