In the output control method for a consumable electrode arc welding power source, entire application range of an welding current is segmentalized into a plurality of current zones, a norm welding voltage value is set for each of the current zones, a welding current and a welding voltage are detected at each of minute cycles, the current zone which corresponds to a detected value of the welding current is selected, a fluctuation range is calculated with the norm welding voltage value of the selected current zone as a center value, a welding voltage limit value is calculated while the welding voltage detected value is limited to within the fluctuation range, and the output of the welding power source is controlled based on this welding voltage limit value.