PURPOSE: To prevent extreme attenuation of a control signal and to improve reliability as a semiconductor device, by providing a bead machining part at a connecting part of a control electrode terminal, which is guided out to an insulated outer container, and an external circuit lead,and performing resistance welding.

CONSTITUTION: A terminal 2, whose cross section is of an L shape, is attached to a cathode post 1, to which an annular insulator 5 is attached. A lead 3 is fixed to the terminal 2 by resistance welding. A bead machining part 4 having a thickness of 50∼300μm is provided at the lead 3. Under the stacked state of the lead 3 and the part 4, pressure is applied at 50∼500kg/cm2 in an inactive gas atmosphere or in air, and a current, whose peak value is 5,000∼50,000A, is applied. Thus the resistance welding is performed. The bead machining part 4 can be formed on the terminal 2. The shape of the terminal is not limited to the L shape, but a flat shape can be partially provided or the entire body is made flat.