An FeRAM is produced by a method including the steps of forming a lower electrode layer, forming a first ferroelectric film on the lower electrode layer, forming on the first ferroelectric film a second ferroelectric film in an amorphous state containing iridium inside, thermally treating the second ferroelectric film in an oxidizing atmosphere to crystallize the second ferroelectric film and to cause iridium in the second ferroelectric film to diffuse into the first ferroelectric film, forming an upper electrode layer on the second ferroelectric film, and processing each of the upper electrode layer, the second ferroelectric film, the first ferroelectric film, and the lower electrode layer to form the capacitor structure. With such a structure, the inversion charge amount in a ferroelectric capacitor structure is improved without increasing the leak current pointlessly, and a high yield can be assured, thereby realizing a highly reliable FeRAM.