A display device including a display area and a non-display area further includes a base layer including a first surface and a second surface opposite to the first surface, the base layer having, in the non-display area, an opening portion penetrating the first surface and the second surface; a pad unit including a terminal on the first surface, the pad unit extending from the first surface to the opening portion; a connection line connected to the terminal on the first surface, the connection line extending from the non-display area to the display area; an insulating layer covering the terminal and the connection line; a thin-film transistor including a semiconductor layer on the insulating layer, the thin-film transistor being connected to the connection line; and a display element connected to the thin-film transistor, the display element being in the display area.