There is provided a driving circuit capable of driving current flowing in cathode electrodes with high accuracy and displaying without brightness variation. For driving a cathode electrode in a display panel, a first current mirror circuit is fabricated by connecting a gate of first FET and a gate of second FET and a second current mirror circuit is fabricated by connecting a gate of a third FET connected in series to the second FET and a gate of a fourth FET. A brightness signal controls the magnitude of current flowing in the first FET, so that the current flowing to the cathode electrode via the fourth FET can be controlled with high accuracy.