The present invention provides a display device which is used in a miniaturized portable information device, wherein the display device requires a small mounting area for a driving circuit thus realizing free mounting of the driving circuit and also can perform driving thereof with a low-voltage power source such as a battery. In a display device which includes a display panel and a driving circuit on the same substrate, a booster circuit is formed on one side of a display panel together with the driving circuit and is formed by steps substantially equal to steps for pixel transistors. The booster circuit includes a circuit which compensates for the lowering of voltage of a switching element used in the booster circuit attributed to a threshold value of a switching element.