To solve the problems that the strength of a ceramic plate is reduced by forming an opening part on the surface of the ceramic plate for carrying a current to a stud welding pin, the stud welding pin becomes worn to peel the ceramic plate when the stud welding pin is exposed on the surface of the ceramic plate, and the ceramic plate needs to be thick for fitting the stud welding pin.

A copperplate having a current-carrying function is inserted between the ceramic plate and the stud welding pin and brazed, thereby mitigating the thermal stress caused by the brazing of the ceramic plate and the stud welding pin, and improving current-carrying properties to the stud welding pin.