An LCD device includes a plurality of gate lines and a plurality of shift register units for driving corresponding gate lines. Each shift register unit includes a first circuit and a second circuit. The first circuit, disposed on a first side of a corresponding gate line, includes a pulse generator and a first transistor having a first W/L ratio. The pulse generator provides a driving signal according to the voltage obtained at a node, while the first transistor maintains the voltage level of the node. The second circuit, disposed on a second side of the corresponding gate line, includes a second transistor having a second W/L ratio. The second transistor maintains the voltage level of the driving signal from the second side of the corresponding gate line. The first W/L ratio is smaller than the second W/L ratio, and the first circuit occupies larger space than the second circuit.