The present invention provides a method for forming a ferroelectric spontaneous polarization reversal capable of forming a ferroelectric spontaneous polarization reversal condition homogeneously within the ferroelectric spontaneous polarization reversal region even across a large region of 50 μm and over in width of a ferroelectric spontaneous polarization reversal. Also, it provides a method for forming a ferroelectric spontaneous polarization reversal where a ferroelectric substrate has convexo-concave structure, such as ridge structure and the like, on its surface and the polarity of the region including one portion of said convex part is reversed with accuracy. A method for forming a ferroelectric spontaneous polarization reversal in a desired region of a ferroelectric substrate 1 has a feature that said desired region 20 of a surface of said ferroelectric substrate is sprayed with micro-hard materials, made an impact by using a striking member that has micro tip diameter, or rubbed with micro-hard materials that are dispersively located on the surface of the substrate to thereby generate nucleuses, and subsequently, a given voltage is applied into said desired region to thereby form a ferroelectric spontaneous polarization reversal in said desired region of said ferroelectric substrate. Also, a method for forming a ferroelectric spontaneous polarization reversal where a convexo-concave structure is formed on a top face of a ferroelectric substrate firstly, and then, a ferroelectric spontaneous polarization region is formed on the substrate including one portion of said convex part, has a feature that a concave portion is formed on a bottom face of the substrate within the region where a ferroelectric spontaneous polarization reversal is to be formed and at least said convex portion is formed, and then, an electric field is applied into said substrate.