A touch display device, comprising: a display panel; a controller to generate a touch sync signal for controlling timing of a touch sensing period and a display period in each of a plurality of frames, the touch sensing period and the display period alternating with each other; a self cap type touch panel built in the display panel and having a plurality of touch electrodes in a display area of the touch display device, the touch panel to generate touch sensing signals indicating whether or not a touch occurs during the touch sensing period; a touch sensing circuit to supply a touch drive signal to the plurality of touch electrodes during the touch sensing period and to detect if the touch occurred based on the touch sensing signals; a first transfer line (VGLL) to supply a first DC drive voltage during the display period and to supply a gate line auxiliary drive signal during the touch sensing period; a second transfer line (VGHL) to supply a second DC drive voltage during the display period and during the touch sensing period; a gate driver to supply gate pulses to gate lines of the touch panel during the display period to activate respective rows of pixels to receive pixel data, the gate driver to supply the gate pulses by switching between driving the first DC drive voltage from the first transfer line (VGLL) onto the gate lines and driving the second DC drive voltage from the second transfer line (VGHL) onto the gate lines, the gate driver further to supply the gate line auxiliary drive signal from the first transfer line (VGLL) onto the gate lines during the touch sensing period, the gate line auxiliary drive signal having the same AC waveform, including amplitude and phase as the touch drive signal; one or more auxiliary lines to supply a supplemental auxiliary drive signal during the touch sensing period, the one or more auxiliary lines adjacent to the first transfer line (VGLL), the supplemental auxiliary drive signal having the same oscillation period, phase and amplitude as the touch drive signal, the one or more auxiliary lines comprising a first auxiliary line disposed between the first transfer line (VGLL) and the second transfer line (VGHL). a display panel; a controller to generate a touch sync signal for controlling timing of a touch sensing period and a display period in each of a plurality of frames, the touch sensing period and the display period alternating with each other; a self cap type touch panel built in the display panel and having a plurality of touch electrodes in a display area of the touch display device, the touch panel to generate touch sensing signals indicating whether or not a touch occurs during the touch sensing period; a touch sensing circuit to supply a touch drive signal to the plurality of touch electrodes during the touch sensing period and to detect if the touch occurred based on the touch sensing signals; a first transfer line (VGLL) to supply a first DC drive voltage during the display period and to supply a gate line auxiliary drive signal during the touch sensing period; a second transfer line (VGHL) to supply a second DC drive voltage during the display period and during the touch sensing period; a gate driver to supply gate pulses to gate lines of the touch panel during the display period to activate respective rows of pixels to receive pixel data, the gate driver to supply the gate pulses by switching between driving the first DC drive voltage from the first transfer line (VGLL) onto the gate lines and driving the second DC drive voltage from the second transfer line (VGHL) onto the gate lines, the gate driver further to supply the gate line auxiliary drive signal from the first transfer line (VGLL) onto the gate lines during the touch sensing period, the gate line auxiliary drive signal having the same AC waveform, including amplitude and phase as the touch drive signal; one or more auxiliary lines to supply a supplemental auxiliary drive signal during the touch sensing period, the one or more auxiliary lines adjacent to the first transfer line (VGLL), the supplemental auxiliary drive signal having the same oscillation period, phase and amplitude as the touch drive signal, the one or more auxiliary lines comprising a first auxiliary line disposed between the first transfer line (VGLL) and the second transfer line (VGHL).