An identification device according to the present invention that performs authenticity determination of an article provided with an anti-counterfeiting medium whose observed light pattern changes depending on an observation angle includes a similarity calculating unit that calculates a degree of similarity between captured image data of the anti-counterfeiting medium and reference image data; an authenticity determination unit that performs authenticity determination as to whether the anti-counterfeiting medium is genuine or not on the basis of whether the degree of similarity exceeds a predetermined threshold or not; and a match-percentage notification unit that notifies a match-percentage indicative of a degree of match between an imaging viewpoint for imaging the anti-counterfeiting medium and a reference imaging viewpoint which is predefined as the imaging viewpoint for the captured image data used for authenticity determination.