Every time to-be-verified biometric is input, the apparatus reflects the degree of fluctuation in the to-be-verified biometric information on narrowing down of registered feature information. After to-be-verified biometric information is input through the a biometric information input unit, the to-be-verified sub-feature information obtaining unit extracts two or more items of sub-feature information from the to-be-verified biometric information. Based on the pieces of to-be-verified sub-feature information, the to-be-verified sub-feature information assessing unit assesses an acquisition stability of each item of to-be-verified sub-feature information. According to the acquisition stability assessment, the registered feature information narrowing unit selects one or more pieces of registered feature information to be subjected to comparison/verification, thereby narrowing down the registered feature information. The apparatus applicable to 1-to-N verification using biometric information such fingerprints, palm prints, iris patterns, facial images, voice patterns, and blood vessel patterns.