An arc welding method by which welding conditions such as the welding speed, the voltage and the current can be varied easily. A starting point at which the change of the welding conditions, i.e., the welding speed, voltage and current, is started and a finishing point at which the change of the conditions is finished are taught, and the welding speeds, voltages and currents at those starting and finishing points are determined. At the starting point, the welding is started at the welding speed, voltage and current which are set as the conditions at the starting point and the welding conditions are gradually changed so as to reach, at the finishing point, the welding speed, voltage and current which are set as the conditions at the finishing point. Only by setting the positions of the starting point and finishing point and the welding conditions at the positions, the welding conditions can be gradually changed while a welding torch is moved from the starting point to the finishing point, so that the welding conditions can be varied easily.