Abstract: A continuous lap-seaming electrical resistance welding machine for can bodies is disclosed. Two electrode units together define a welding passage, through which laps of sheet metal are passed for welding. Each of the electrode units comprises a band electrode running over an electrode roller having a stationary axis. A band guide roller spaced from the electrode roller(s) in continuation of the welding passage forms a straight-line section between the electrode roller(s) and the associated guide roller. Preferably the guide roller is disposed downstream of electrode roller relative to the direction of displacement of the laps through the welding passage.