Fingerprint images that are required for fake-finger determination can be acquired with a single input operation, and the user-friendliness and the determination accuracy of a fake-finger are improved. This device has moving means for moving a sensor surface, on which a finger as a determination object is placed, relatively to the finger, sensing means for acquiring fingerprint images of the finger before and after the sensor surface is moved, derivation means for obtaining a deformation level of the fingerprint before and after the sensor surface is moved based on two types of fingerprint images obtained by the sensing means, storage means for storing a deformation threshold related to the deformation level of the fingerprint to determine whether the finger on the sensor surface is a real finger or a fake-finger, and determination means for determining whether the finger placed on the sensor surface is a real finger or a fake-finger based on comparison results of the deformation level of the fingerprint obtained by the derivation means and the deformation threshold.