When respective bits of grayscale data Dx1 are `0` which represents black, upon detection, a NOR circuit of a voltage supply circuit sets an output signal active. Then, a transistor is turned on, and a black voltage VBr is supplied to a data line. By this embodiment, since all transistors of a current supply circuit are turned off, a current is not outputted. Meanwhile, in the case in which a grayscale level to be displayed is other than black, a current Idata is outputted from the current supply circuit.