A fingerprint image necessary for fake finger discrimination can be acquired with a single input operation, and fake finger discrimination accuracy is improved along with convenience. Obtained by a moving means for moving a sensor surface on which a finger as a discrimination target is placed relative to the finger, a sensing means for acquiring fingerprint images of the finger before and after the movement of the sensor surface, and a sensing means. Based on the obtained two types of fingerprint images, a derivation means for obtaining the degree of deformation of the fingerprint before and after the movement of the sensor surface, and a memory for storing a deformation threshold relating to the degree of deformation of the fingerprint for determining whether the finger is a real finger or a fake finger And a discrimination means for discriminating whether the finger placed on the sensor surface is a real finger or a fake finger based on a comparison result between the deformation degree of the fingerprint obtained by the derivation means and the deformation threshold value. Is provided.１回の入力動作で偽指判別のために必要な指紋画像を取得することができ、利便性とともに偽指の判別精度を向上させる。判別対象物としての指が載置されるセンサ面を、該指に対して相対的に移動させる移動手段と、センサ面の移動前後における指の指紋画像を取得するセンシング手段と、センシング手段によって得られた２種類の指紋画像に基づき、センサ面の移動前後における指紋の変形度合いを求める導出手段と、本物の指か偽指かを判別するための指紋の変形度合いに関わる変形閾値を記憶する記憶手段と、導出手段が求めた指紋の変形度合いと変形閾値との比較結果に基づいて、センサ面に載置された指が、本物の指であるか偽指であるかを判別する判別手段とを備える。
