To a manufacture a large-sized gradient composition body in which the component compositions of adjacent parts are mutually mixed in the boundary and not sharply changed in the boundary.

One or more pieces of partition walls 10a are provided in a forming mold 8 composed of an outer mold 8a, core metal 9 and bottom 8b and the powders A, B are charged into each chamber divided with the partition wall 10a so as to be different from adjacent chamber. After filling up in each chamber, a table 2 is descended and the partitioning wall 10a is removed, and the powder is formed while applying vibrations to the forming mold 8 so as to generate the mixed layer near the position where the partition wall 10a has been provided.