The present invention relates to a source driver for a display apparatus, which is capable of removing delay of a DAC (Digital-Analog Converter) and in which a part of gamma lines for providing gamma voltages to the DAC is designed to have a large width and a small resistance value. Before driving a first gamma voltage to a level corresponding to display data, the DAC can select an adjacent gamma line having a small resistance value and drive a second gamma voltage, thereby removing a delay time.