Provided is a display device. The display device includes: a pixel including an emissive element circuit, a reflective element circuit, and a switch transistor selecting one of the emissive element circuit and the reflective element circuit; an illumination sensor generating an illumination information signal according to an illumination of an external light source by detecting the external light source; and a controller generating control signals for driving the pixel according to pixel data, wherein the controller generates a light signal controlling the switch transistor by referencing the illumination information signal.