PURPOSE: To provide an electrode for welding by which a setting defect of a welding nut, welding bolt and member to be welded is surely detected through a simple mechanism and in addition a guide pin is used for a long term.

CONSTITUTION: A conductive actuating lever 4, which is freely movable vertically, is inserted in the main body 1 of an electrode tip facing to an upper electrode 22, an insulating cylindrical body 3, by which a contact pin 10 placed opposite to the base end of the operating rod 4 with a prescribed space apart is repulsively supported in a freely retreative state, is attached to the base end of the main body 1 of the electrode tip, and simultaneously, a circuit 21 for detecting a setting abnormality is formed which consists of the operating rod 4 and the contact pin 10. In addition, a guide pin 5 composed of an insulating material is provided on the upper end of the operating rod 4, which is then connected electrically with the main body 1 of the electrode tip.