A cognitive impairment diagnostic apparatus includes: a display which displays a video for diagnosis of cognitive impairment on a display surface; an imaging unit which captures images of an eye of a subject; a detection unit which detects viewpoints of the subject on the display surface in time series based on the images captured by the imaging unit; a creation unit which creates a distribution map representing a distribution of the viewpoints detected by the detection unit; a storage unit which stores case characteristic data indicating a characteristic of a viewpoint distribution corresponding to a typical case in cognitive impairment; and a diagnostic unit which diagnoses cognitive impairment of the subject by determining whether the distribution map has the characteristic indicated by the case characteristic data.