A cognitive impairment diagnostic device (1) comprises an acquisition unit (41) for acquiring a distribution map indicating a distribution of view points of a subject with respect to a diagnosis video, and a diagnostic unit (39), the diagnosis video including, in time order: first video having a first region including a visually highlighted memorization image, and a plurality of second regions including normal images displayed without highlighting; and evaluation video having a third region including an evaluation image that is similar to the memorization image and that is displayed without visual highlighting in the same position as the memorization image, and a plurality of second regions, and the diagnostic unit (39) calculating a gaze rate for the third region in the distribution map with respect to the evaluation video and diagnosing suspected cognitive impairment when the gaze rate is lower than a threshold value.
