A method for forming a wiring according to the present invention includes: applying an ink (6) that exhibits electrical conductivity upon light absorption to a contact hole formation portion of an upper face of an insulating resin layer (3) formed on a lower wiring element (2); and irradiating the ink (6) with light to render the ink (6) conductive and also to remove a part of the insulating resin layer (3) by heat emitted from the ink (6) so as to form a contact hole (5), the part of the insulating resin layer (3) lying under the portion of the face to which the ink (6) is applied. A step of forming an upper wiring element (4) on the upper face of the insulating resin layer (3) may further be carried out, the upper wiring element (4) being electrically continuous with the lower wiring element (2) through the contact hole (5).