A semiconductor device includes MOS transistors, capacitor elements, a voltage generating circuit, a contact plug, and a memory cell. The MOS transistor and the capacitor element are formed on a first one of the element regions and a second one of the element regions, respectively. In the voltage generating circuit, current paths of the MOS transistors are series-connected and the capacitor elements are connected to the source or drain of the MOS transistors. The contact plug is formed on the source or the drain to connect the MOS transistors or one of the MOS transistors and one of the capacitor elements. A distance between the gate and the contact plug both for a first one of the MOS transistors located in the final stage in the series connection is larger than that for a second one of the MOS transistors located in the initial stage in the series connection.