1. A fingerprint authenticating system comprising: a fingerprint registering unit; and a fingerprint collating unit, wherein said 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, said 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, and an area of said first portion is equal to or larger than an area of said second portion.