An in-plane switching mode liquid crystal display device includes first and second opposed substrates having inner surfaces in which a liquid crystal layer formed therebetween, a data bus line and a gate bus line arranged perpendicularly and/or horizontally in a matrix on the first substrate thereby defining a unit pixel region, and a pair of data electrode and common electrode applying a plane electric field in the liquid crystal layer, the electrodes being inclined with respect to the data bus line and parallel to each other.