According to one embodiment, a display device includes a plurality of first lines, a plurality of second lines, a plurality of switch elements, a plurality of pixel electrodes, a plurality of third lines, a display layer, and a controller. The plurality of first lines extend in a first direction. The plurality of second lines extend in a second direction. The plurality of third lines extend in the second direction. The switch elements are electrically connected to the first lines and the second lines. The pixel electrodes are connected to the switch elements. The display layer performs an optical operation based on an electrical signal applied to the pixel electrodes. The controller includes at least one switch connected between the second lines and the third lines.