1. A cognitive function training unit for training a cognitive function of a subject comprising: an eye-target showing means for showing a movable eye-target on a display disposed in front of the subject's eye; an eye movement measuring means for measuring a position and/or movement of the subject's eye; a judgment means for judging whether the subject can fixedly look at or follow the eye-target based on the position and/or the movement of the eye-target shown on said display and the position and/or the movement of the subject's eye measured by said eye movement measuring means; wherein said eye-target showing means shows the eye-target repeatedly while changing the position and/or the movement of the eye-target according to a judgment result of said judgment means.