At least two types of dielectric materials such as oxide nanosheets having a layered perovskite structure that differ from each other are laminated, and the nanosheets are bonded to each other via an ionic material, thereby producing a superlattice structure-having ferroelectric thin film. Having the layered structure, the film can exhibit ferroelectricity as a whole, though not using a ferroelectric material therein. Accordingly, there is provided a ferroelectric film based on a novel principle, which is favorable for ferroelectric memories and others and which is free from a size effect even though extremely thinned.