A display device includes a substrate including a first surface, a plurality of pixel units on the first surface, and a first side wiring pad located in a first outermost array adjacent to a first side on the first surface and located between adjacent pixel units of the plurality of pixel units in a direction along the first side. A plurality of pixel units in the first outermost array can be arranged in a portion adjacent to an edge on the first surface of the substrate. A joint pixel pitch can thus be easily equalized to a non-joint pixel pitch, although the non-joint pixel pitch is smaller.