A wiring substrate includes a signal supply unit, a plurality of wirings disposed in a wiring region in which an intermediate region is interposed between the wiring region and the signal supply units, and having different distances from the signal supply unit, and a plurality of coupling wirings disposed in the intermediate region, and coupled to the signal supply unit and the plurality of wirings, in which the plurality of coupling wirings includes a first coupling wiring coupled to a wiring having a short distance from the signal supply unit, and a second coupling wiring coupled to a wiring having a long distance from the signal supply unit among the plurality of wirings, and the first coupling wiring is folded back to the signal supply unit side in the middle of running from the signal supply unit to the wiring region.