A display device, which includes a plurality of pixels; a data driver for outputting data signals to the pixels; a bias current outputting unit for outputting a bias current having a predetermined magnitude; a plurality of driving current outputting units for outputting driving currents to the pixels; and a first switch connected between the bias current outputting unit and the driving current outputting units for selecting one of the driving current outputting units to connect to the bias current outputting unit, wherein the magnitudes of the driving currents are substantially the same as a magnitude of the bias current.