To provide a method for detecting an energized state between an electrode and a holding part of a member to be welded before flash welding.

Electrodes 3A, 3B, 4A, 4B for holding two members 1, 2 to be welded are prepared at least for two sets and, before abutting two members 1, 2 on each other, a detecting current is flowed in a feeding transformer 5 to which one set of electrodes 3A, 3B is connected, determining the current of its primary side 9, or the current or impedance of the circuit which is formed with the secondary side 7 and the feeding transformer 6 on the side of the other set of electrodes 4A, 4B. These values are each compared with a current or impedance in the normal condition so that the energized state is detected in the holding part.