Discussed are a built-in gate driver capable of improving output characteristics of the gate driver by reducing load of clock lines and a display device using the same. The built-in gate driver can include a shift register, a first clock group and a second clock group located in a non-display region of a display panel. The shift register includes a plurality of stages for individually driving gate lines of a display region. The first clock group includes clock lines arranged at a first side of the shift register. The second clock group includes clock lines arranged at a second side of the shift register. Each of the clock lines includes a main line and a branch line branched from the main line and connected to a corresponding stage. A branch line belonging to a corresponding clock group of any one of the first and second clock groups does not overlap a main line belonging to the other clock group.