A semiconductor integrated circuit including a large capacity reservoir capacitor to provide suitable power is provided. The semiconductor integrated circuit includes a semiconductor substrate in which a cell area and a peripheral circuit area are defined, a MOS capacitor formed on the semiconductor substrate corresponding to the peripheral circuit area, and a dummy capacitor group formed on the peripheral circuit area to overlap the MOS capacitor. One electrode of the MOS capacitor and one electrode of the dummy capacitor group are connected to each other and the other electrode of the MOS capacitor and the other electrode of the dummy capacitor group are connected to difference voltage sources from each other.