A driver fatigue assessment device may include； a look information generator to generate look information regarding at least one of a driver's direction of a look and a locus at which a driver is looking； a visual stimulator to provide a visual stimulus within a driver's field of view at a first position and then move the location thereof to a second position； a change determination unit to determine whether the look information has changed in response to the movement of the visual stimulus； and a fatigue decision unit to assess driver fatigue based upon an output of the change determination unit.
