A circuit board includes a substrate; a plurality of scan lines disposed on the substrate, the scan lines extending in a first direction; a plurality of signal lines disposed on the substrate, the signal lines extending in a second direction intersecting the first direction; a plurality of transistors, each of which is electrically connected to corresponding one of the plurality of scan lines and corresponding one of the plurality of signal lines; an insulating layer that covers the plurality of scan lines, the plurality of signal lines, and the plurality of transistors; and a plurality of electrodes, each of which is electrically connected to corresponding one of the plurality of transistors. One opening is formed in the insulating layer for every electrode group, the electrode group being constituted by at least two adjacent electrodes among the plurality of electrodes, and each of the plurality of electrodes is electrically connected to the corresponding one of the transistors through the opening.