An auto probe device used in a method of testing a plurality of signal lines of a liquid crystal panel includes a printed circuit board having a shorting bar, a flexible printed circuit board having a plurality of connection patterns electrically connected to the shorting bar of the printed circuit board, and a plurality of contact pins contacting the plurality of pads formed in a non-display area of the liquid crystal panel. Such an auto probe device reduces a defect generation rate in a lighting test of the liquid crystal panel so that accuracy of the lighting test may be improved.