A display device, including a pixel array substrate and a sensor element substrate, is provided. The sensor element substrate overlaps the pixel array substrate, and includes a substrate, a switch element, and a photosensitive element. The switch element is located on the substrate. The photosensitive element is electrically connected to the switch element, and includes a transparent electrode, a sensing layer, a metal electrode, and a barrier layer. The sensing layer is located on the transparent electrode. The metal electrode is located on the sensing layer, and covers a first sidewall of the sensing layer. The barrier layer covers a first sidewall of the transparent electrode. The barrier layer is located between the metal electrode and the sensing layer, or between the transparent electrode and the sensing layer.