A method for measuring a residual DC voltage in a liquid crystal device including an active region having a plurality of liquid crystal capacitors and a plurality of TFTs, and a non-active region positioned outside the active region and having at least one monitoring capacitor, in which the plurality of liquid crystal capacitors and the at least one monitoring capacitor include a liquid crystal layer. The method includes: generating a V-I curve by applying a positive and negative symmetrical triangular wave voltage measuring, in the V-I curve, a voltage Vmax having a maximum absolute value where a current value reaches a positive maximum value or minimum value, and a voltage Vmin having a maximum absolute value where a current value reaches a negative minimum value or maximum value, and measuring one-half of the sum of the voltage Vmax and the voltage Vmin as the residual DC voltage.