A manufacturing method of a display device, which prevents electrostatic breakdown of the display device both before and after a circuit test without reducing the productivity in forming a plurality of display devices on a substrate to be processed by a step-and-repeat exposing method. A wiring pattern group led out from signal input terminals of the display devices to the edge of the substrate to be processed is efficiently formed by exposing to light through a repetitive pattern integrated with a display device pattern. Depending on the states of the wiring pattern group as to contact or non-contact with a detachable and conductive component, the signal input terminals of the display devices can be easily switched between in a short circuited state and a non-short circuited state. Accordingly, both the measure against electrostatic breakdown and the circuit test are achieved in the display devices on the substrate to be processed.