A display driver for evenly display the screen driven by a plurality of driver circuits is provided. The display apparatus includes a display panel driven by data lines and driver units. Each of the data lines is driven by the corresponding driver unit. Each of the driver units has a resistance division unit for generating grayscale voltages, an operational amplifier unit for supplying voltages to the terminals of the resistance division unit in response to a bias control signal. The corresponding terminals of the resistance division unit of the plurality of driver circuits are commonly connected. The bias control signal is supplied when each of the driver circuit drives the corresponding data line.