In a method of fabricating a lightweight and thin liquid crystal display (LCD), when an auxiliary substrate is used to perform a process of a thin glass substrate, the auxiliary substrate is separated from the thin glass substrate by detaching an edge portion between the thin glass substrate and the auxiliary substrate using a knife and then injecting air into the edge portion using an air knife, so that the auxiliary substrate can be easily separated from a liquid crystal panel in a cell state, which is attached by completing the process. Further, it is possible to optimize the shape of a push pin for forming a point at which the detachment of the edge portion is started.