A zirconia sintered body having high strength and high toughness is provided, and a method for producing the same is also provided. The zirconia sintered body comprising tetragonal zirconia, wherein a full width at half maximum at (111) plane of the tetragonal zirconia obtained by X-ray diffraction pattern is from 0.38 to 4 degree. A method for producing the zirconia sintered body, wherein the method comprises steps of; molding zirconia powder having an average particle diameter of from 0.1 to 0.6 .mu.m, a maximum particle diameter of 5 .mu.m or less and a substantially polyhedral shape, and then sintering the molded green body under the temperature of from 1200 to 1400.degree. C.