To obtain a sintered body having good characteristics from a granulated powder, and especially stably obtain a sintered body of high strength by controlling the variation coefft. of the compressive strength of granulated particles which constitute the granulated powder for forming to a specified value or lower.

A source material powder having 0.5-1.0μm average particle size is dispersed in a liquid such as water and alcohols to obtain a slurry, or an org. binder for granulation is added by 0.01-2wt.% to the slurry. The obtd. slurry is spray-dried by a spray dryer or the like to obtain a granulated particle for forming having 50-100μm average particle size. The coefft. of variation of compressive strength (standard deviation of strength/average strength) of the granulated particle which constitutes the obtd. granulated powder is maintained to ≤0.3. The granulated powder is press formed, and if an org. binder for granulation is added, the compacted body is treated to remove the binder, and then compacted body is calcined to obtain a sintered body.