In the manufacture of a display device, an object of the invention is to make it possible to easily and precisely measure the amount of beveling of the display panel without an increase in manufacturing costs. In the process of manufacturing a display device, a shorting interconnection (10) is provided near edges of the display panel in order to short-circuit signal interconnections and scanning interconnections (interconnections 3). In a final stage, the shorting interconnection (10) is removed together with a beveled area (A2) by the beveling of the edges of the display panel. The interconnections (3) have marks (11) that are formed near the edges of the substrate and used as reference for the amount of beveling. Each mark (11) is located in a position shifted from the mark (11) of an adjacent interconnection (3) along the length of the interconnections (3).