Reference voltage generation means is constituted by including first voltage division means constituted so as to be able to generate a plurality of levels of gradation display voltages by resistance-dividing voltage differences between a plurality of reference voltages VR by a plurality of dividing resistors connected in series, second voltage division means constituted so as to be able to generate some or all of the gradation display voltages by resistance-dividing voltage differences between a plurality of reference voltages VR by a plurality of auxiliary resistors connected in series, and switching means for mutually connecting all or a part of the plurality of gradation display voltages generated by the first voltage division means and the second voltage division means. The switching means is turned on during the transient state period in which the DA conversion circuit responds and the first and second voltage division means operate.