a fingerprint authenticating system includes a fingerprint registering unit and a fingerprint collating unit . the fingerprint registering unit takes a first fingerprint data indicating a first portion of a first fingerprint from a first fingerprint sensor , registers said first fingerprint data to a memory unit , and takes a second fingerprint data indicating a second portion of a second fingerprint from a second fingerprint sensor . the fingerprint collating unit collates said second fingerprint data with said first fingerprint data to confirm whether or not said first fingerprint is equal to said second fingerprint . here , an area of the first portion is equal to or larger than an area of the second portion .