A display device including a pair of opposed substrates at least one of which is transparent with a display medium layer therebetween, and a transparent electrode arranged on the internal surface of the transparent substrate is provided. The thickness of the transparent electrode is about (5500/(2.times.n)).ANG. wherein n represents the refractive index thereof. When a transparent insulating film is formed on the transparent electrode, the thickness of the transparent insulating film is about (5500/(2.times.m).ANG. wherein m represents the refractive index thereof. When the refractive index of n.sub.1 of the transparent insulating film is substantially equal to the refractive index n.sub.2 of the transparent electrode, the value, 2.times.(n.sub.1 .times.d.sub.1 +n.sub.2 .times.d.sub.2) equals about 5500.ANG. wherein d.sub.1 represents the thickness of the transparent insulating film and d.sub.2 the thickness of the transparent electrode.