The invention discloses an 
electric resistance welding method, an 
electrode welding head using the 
electric resistance welding method and the 
electrode welding head used in the 
electric resistance welding method. The electric resistance 
welding method includes the steps that welding parts to be welded are connected together in a 
lap joint and a vertically intersected overlaying or overlapping mode, then two electrodes are pressed on a welding part on the top layer in advance in the same direction to form a 
current loop, pressurizing pieces are arranged between the two electrodes and on the same side as the electrodes, wherein the pressurizing pieces are parallel to the electrodes and can vertically move to press the welding part on the top layer, and in the process of welding, the electric resistance welding method includes the following steps that (1) a power supply of a welding 
machine is switched on, (2) current generates resistance heat in the welding part on the top layer, and the welding part on the top layer is heated to a fusion or plastic state, (3) the pressurizing pieces pressurize the welding part on the top layer, (4) cooling 
crystallization is conducted, (5) pressure of the pressurizing pieces and the two electrodes is released, and then the welding parts are taken out. By the adoption of the electric resistance welding method, any 
metal wire or wire or wire piece or piece in a 
lap joint state can be welded, the electric resistance welding method is especially used for welding IC card chips and induction coils of the IC card chips and directly welding battery electrodes and 
copper pieces or 
copper wires in battery sets and can achieve the good effect.