A comparison apparatus 2 designates first registration information RT1 inherent to a first parameter obtained by applying generalized Hough transform processing to a registered image AIM based on the set first parameter as the registration information RT1 used for the comparison and, designating second registration information RT1 obtained by applying generalized Hough transform processing to the registered image AIM based on a second parameter different from the first parameter as the registration information RT1 used for the comparison when receiving an instruction for change of the registration information RT1 after the designation, whereby security can be improved.