PURPOSE: To obtain ceramic powder without contg. an agglomerate, having submicron/nanosize and uniform in size by curing a mixture of metal cation salt and an org. precursor, etc., of a polymeric foam and then, burning the cured mixture in a prescribed condition.

CONSTITUTION: An aq. soln., etc., of metal cation salt (nitrate or the like of La, Sr, Cr or the like) and an org. precursor (polyol and diisocyanate) or the like of a polymeric foam are mixed and cured. Then, the polymeric foam (polyurethane foam) in which the metal cation is homogeneously incorporated within a foam cell structure is formed. Then, the foam is burned under the condition at 400-1,400°C for 1 min-96 hr to completely remove all the org. materials and to form a crystalline phase. In this way, the ceramic powder having high air sintering property such as La0.78Sr0.22CrO3-r is obtained.