A user authentication system performs user recognition with a higher accuracy based on acquired bodily information, in which multiple users use multiple types of bodily information acquisition apparatuses to acquire different types of bodily information. The user authentication system includes multiple types of bodily information acquisition apparatuses for acquiring different types of information for a certain user； a unit stores pieces of bodily information acquired by the respective bodily information acquisition apparatuses, in association with certain user； and a user determination unit checks whether there is a logical discrepancy between new bodily information acquired newly by a certain bodily information acquisition apparatus among the plurality of types of bodily information acquisition apparatuses and other bodily information acquired by a bodily information acquisition apparatus other than the certain bodily information acquisition apparatus, and determine whether the new bodily information acquired by the certain bodily information acquisition apparatus relates to the certain user.
