1. An element splitting method to be applied to a finite element analysis, comprising: (1) a step to dispose an object region in a coordinate system and to determine a coordinate of a point on a boundary line which includes an outline of the object region; (2) a step to split the object region by a Delaunay triangulation by using the coordinate of the point on the boundary line, determined in the step (1), as a nodal point; (3) a step to elect an arbitrary coordinate in the coordinate system by a Monte Carlo method and to judge whether the coordinate is within the object region or not; (4) a step to sequentially suppose a circle having a center at the coordinate judged to be within the object region in the step (3) by determining a radius of the circle based on a predetermined function, and to adopt the supposed circle when the supposed circle does not intersect with any existing circles; (5) a step to extract one circle out of all of circles adopted in the step (4) by the Monte Carlo method, to specify six circles having minimum intervals from the one circle, to provisionally move the center coordinate of the one circle by the Monte Carlo method, to calculate values of degrees of dispersion of intervals from the one circle before and after the movement, and to adopt the center coordinate after movement when the value of the degree of dispersion after the movement falls below that before the movement; and (6) a step to split the object region by a Delaunay triangulation by using, as nodal points, the coordinate of the point on the boundary line determined in the step (1) and the center coordinate adopted through the steps of (2) to (5).