For electrically connecting a wiring formed on one surface of an insulating substrate such as an FPC to an individual electrode arranged facing the other surface of the substrate, firstly, a through hole and a notch are formed by irradiating a laser beam from above onto the FPC. Next, the FPC is arranged to be positioned such that the individual electrode, the through hole and the notch are overlapped in a plan view. Next, an electroconductive liquid droplet having a diameter greater than a width of the notch is jetted, toward an area formed with the notch, from the one surface side of the FPC. The landed electroconductive liquid droplet flows along the notch in a thickness direction of the substrate due to an action of a capillary force and reaches assuredly to the individual electrode, thereby electrically connecting the wiring and electrode arranged sandwiching the insulating substrate assuredly.