A method of controlling the amount of firing shrinkage of a ceramic green body prepared by molding a ceramic powder (A) to a desired value A.sub.1 by heat treating the powder at a temperature T.sub.1 that provides the firing shrinkage A.sub.1 at a predetermined firing temperature. The temperature T.sub.1 is determined based on an established correlation between an amount of firing shrinkage at the predetermined firing temperature and a heat-treatment temperature of a powder (B) having a composition similar to that of the powder (A) in such an extent that a total amount of a greatest common content of an individual component common between the powders (A) and (B) in terms of percent is 90% by weight or more, and satisfying such a relation that the spherical diameter of powder (A) is within a range of .+-. 30% relative to the spherical diameter (Rs) of the powder (B) and that its average degree of aggregation (x) is within the range from 1/2 fold to 2 fold relative to the average degree of aggregation (x) of the powder (B).