A fingerprint collating device and a fingerprint collating method which can prevent an illicit use of fingerprint. This nitride-based semiconductor element comprises a plurality of mask layers formed at a prescribed interval to be in contact with the upper surface of the underlayer while partially exposing the underlayer and the nitride-based semiconductor layer, formed on the upper surface of the underlayer and the mask layers, consisting of the material different from that of the underlayer. The PDN GW provides a backup channel for the CPE to reach the wide area network over a mobile tunnel.