To propose a welding method which can perform welding under time serial correct welding conditions and in a resistance welding mode by inputting extremely few, and above all, materials and sheet-metal gages of materials to be welded in performing resistance welding and above all a method for setting the welding conditions, etc., of this time.

A resistance welding machine 100 to which the output signal with lapse of time is sent from a timer 20 and which is operated according to the output signal is connected with a programmable controller 30 to the timer 20. A computer 50 is connected through a communication line 40 to the programmable controller 30 so that welding information can be inputted to the programmable controller 30 by the computer 50. The reference welding conditions set by each of the materials and sheet-metal gages of the materials to be welded are previously registered in the programmable controller 30 prior to welding and the welding conditions are set in accordance with the reference welding conditions within the programmable controller.