A liquid crystal display device includes a liquid crystal panel having liquid crystal pixels on regions defined by a plurality of gate lines and a plurality data lines, a gate voltage generator configured to generate a gate high voltage and a gate low voltage, and a gate driver configured to generate gate scan signals to respective gate lines using the gate high and low voltages. The gate scan signals are enabled and shifted sequentially by a predetermined interval. A gate voltage modulating unit is configured to modulate the gate high voltage such that an impulse having a negative polarity is added every predetermined period to the gate high voltage supplied to the gate driver. The gate voltage modulating unit controls a width of the impulse depending on characteristics of the liquid crystal panel to control starting points of predetermined edges of the gate scan signals.