Translucent rare earth oxide sintered article and method for production thereof

A high-purity rare earth metal oxide material powder of purity of 99.9% or over, of which Al content is 5-100 wtppm in metal weight and Si content is 10 wtppm or under in metal weight, and a binder are used to prepare a molding body of which molding density is 58% or over of the theoretical density. The binder is eliminated by thermal treatment, and then the molding body is sintered in an atmosphere of hydrogen or a rare gas or a mixture of them or in a vacuum at a temperature being not lower than 1450° C. and not higher than 1700° C. for 0.5 hour or over to prepare A transparent sintered rare earth metal oxide body represented by a general formula R2O3(R being at least one element of a group comprising Y, Dy, Ho, Er, Tm, Yb and Lu).