An image display device includes an optical scanning part, a drive control part which supplies an electric current to lasers, and a light detecting part. The drive control part supplies an electric current to the lasers while changing a current value at two points or more when a scanning position of the light scanned by the optical scanning part is at a predetermined position outside an effective scanning range. Based on intensity of an inspection-use light detected by the light detecting part, current-light emitting quantity characteristics of the lasers are calculated, and electric currents supplied to the lasers are adjusted based on a result of the calculation.