The level of a storage capacitor line is changed between two types, an H level and an L level. As a result of this change, the voltage applied to a liquid crystal is shifted so that a sufficient voltage is applied to the liquid crystal to perform a display operation. Then, at least one of two voltage levels of the storage capacitor line is used in common with the potential of at least one of plurality of voltage levels which are used in vertical driver which drives the said selection line. Furthermore, the values of the storage capacitance and parasitic capacitance for the storage capacitor line are set within a specific range.