PURPOSE: To facilitate the inspection of a liquid crystal display panel and to improve the accuracy thereof in an inspection method, particulaly that for detecting the short circuit of a data electrode in a TFT type liquid crystal display panel.

CONSTITUTION: A first electric signal having a phase, frequency and amplitude which are constant is inputted to one adjacent data electrode 7-1 and a second electric signal having the same frequency and amplitude as the first electric signal and having the opposite phase is inputted to the other data electrode 7-2. Or one end of the data electrode 7-1 and that of the data electrode 7-2 are electrically connected together and the first electric signal having the phase, frequency and amplitude which are constant is inputted to the other end of the data electrode 7-1 and the second electric signal having the same frequency and amplitude s the first electric signal and having the opposite phase is inputted to one end of the electrode 7-2 respectively, and the central voltage of the first and second electric signals is applied on the common electrode of the display panel. When any unnecessary short circuit occurs between the data electrodes 7-1 and 7-2, the brightness due to the first and second electric signals is varied at a short circuit part, thereby visually detecting the presence and position of the short circuit.