1. A registration apparatus characterized by comprising: dividing means for dividing a blood vessel line included in an image into a plurality of partial lines on the basis of end points and a diverging point of the blood vessel line; extracting means for extracting coefficients of terms corresponding to degrees included in a polynomial equation for an n-th order curve representing each of the plurality of partial lines, characterized in that the extracting means performs substitutions of points included in each of the plurality of partial lines into the polynomial equation for an n-th order curve, changes coefficients of terms corresponding to degrees included in a plurality of polynomial equations obtained from the substitutions until differences in value between left sides and right sides of the plurality of polynomial equations become the minimum, and extracts the coefficients; and generating means for generating data including points at both ends of each of the plurality of partial lines and the coefficients.