A liquid crystal display is provided that allows miniaturization, cost lowering, thickness reduction, and saving of unnecessary spaces of the device, and enhancement of the reliability of the device. If a variable resistor is used to set the DC potential of a VCOM potential, miniaturization of a liquid crystal display is precluded since the size of the variable resistor is large. A DA converter is used instead of a conventional variable resistor as a unit for setting (adjusting) the DC potential of a VCOM potential (counter electrode voltage), and the DA converter is formed on the same glass substrate by using the same process as those of a display area part, to thereby achieve miniaturization of the liquid crystal display.