A scan-line driving device for a LCD apparatus is provided. The scan-line driving device comprises a PWM signal generating circuit, two impedances with different resistance values, a capacitor and two scan drivers. The PWM signal generating circuit outputs a PWM signal with two potentials and a predetermined duty cycle. A terminal of the capacitor is electrically coupled to a ground potential, and the other terminal of the capacitor receives the PWM signal. Each of the scan drivers comprises a core circuit and a transistor. A source/drain terminal of each transistor is electrically coupled to a PWM signal input terminal of a corresponding core circuit and the other terminal of the capacitor, the other source/drain terminal of each transistor is electrically coupled to the ground potential through a corresponding one of the impedances, and the gate terminal of each transistor receives a turn-on control signal.