To form a periodic polarization inversion structure of a short period and uniform thickness by impressing an electric field on a ferroelectric material substrate via electrode pairs composed of conductive materials different from each other, thereby forming polarization inversions in the ferroelectric material substrate.

The electrode pairs 2 are arranged on the surface of the X-cut substrate 1 of the ferroelectric material crystals subjected to single polarization. The electrode pairs 2 consist of comb-shaped electrodes 2a and stripe electrodes 2b having periodic patterns. The comb-shaped electrodes 2a are arranged on the +Z axis side of the ferroelectric material crystals. The electrode pairs 2 consist of electrode materials which are different from each other, and an electrical resistance value R1 of the electrode material of the comb-shaped electrodes 2a and a electrical resistance value R2 of the electrode material of the stripe electrodes 2b are so selected as to be R1>R2. For example, a nickel chromium alloy is used as the electrode material of the comb-shaped electrodes 2a and aluminum as the electrode material of the stripe electrodes 2b. The electric field impression on the ferroelectric material crystals is made by the electrode pairs 2 constituted in this way.