A wiring material is provided by electrically connecting a connecting terminal with two single line conductors arranged in parallel. The connecting terminal is provided with a tube-shaped section for storing two single line conductors, the two single line conductors are inserted into the tube-shaped section, resistance welding is performed by carrying electricity from the external of the tube-shaped section in a status where the tube-shaped section and the single line conductors are mutually brought into contact, and the connecting terminal is electrically connected with the two single line conductors.