1. A fingerprint scanning device for use in identification comprising: a fingerprint image input means adapted to photoelectronically input a specified fingerprint of an entrant, and storing two-dimensional monochrome image data of a ridge pattern of the entrant fingerprint as fingerprint image data; a feature extraction means having a calculator which treats the ridge pattern image with one-dimensional group-delay spectrum transform in X- and Y-directions which has a characteristic of isolating and emphasizing peaks of the individual frequency spectra in the form of differential with respect to a phase component frequency in Fourier transform analysis, and determining group-delay spectra in X- and Y-directions, respectively, as fingerprint feature portions; and a distinction means provided to collate the entrant feature portion with a registrant feature position which is registered by the fingerprint image input means so as to identify the entrant with the registrant when at least one of X-oriented and Y-oriented group-delay spectra is recognized to be the same between the entrant and the registrant by calculating whether Euclidean distances fall short of a predetermined threshold limit upon collating the individual ridge pattern image.