A touch sensor includes a display panel that includes a plurality of pixel electrodes each provided in a corresponding one of a plurality of pixels, and a common electrode shared by the plurality of pixels. The touch sensor also includes a touch panel that detects a position of at least either a finger or a pen. The display panel and the touch panel are superimposed on each other in a vertical direction. The common electrode includes a conductor-area-reduction portion that reduces an area of the common electrode.