To connect an electric wire to a wiring board and effectively avoid the open circuit of the electric wire with a simple structure by pinching a core wire and an insulating cover with a metal, connecting the electric wire to a terminal erected on the wiring board via this metal, then soldering them.

A metal 20 is fitted to a lead wire 14 in advance, and the metal 20 is provided with a caulk section 21 at the root portion and a connection section 22 at the tip portion. The caulk section 21 has a U-shaped cross section, both ends of the U-shaped portion are folded to pinch the insulating cover 13 and the core wire 12 of the lead wire 14, and the caulk section 21 is connected to the lead wire 14. The connection section 22 is pressed to a pin 11 and engaged with the pin 11 to pinch it. A wiring board 8 and the lead wire 14 are connected via a metal pinching the insulating cover 13 and the core wire 12 of the lead wire 14 with a simple structure. Even when the lead wire 14 is repeatedly bent, the stress applied to the core wire 12 is reduced, and an open circuit can be effectively avoided. The drop of the lead wire 14 from the pin 11 can be avoided by soldering.