An arc welding control method by which a base material is welded by using a gas mainly containing carbon dioxide as a shield gas and alternately repeating a short circuit period (Ts) and an arc period (Ta), wherein in the short circuit period (Ts), a welding current is increased from a pre-arc regeneration current value lower than a current value at a time of arc generation that is a time of short circuit opening to a first current value in the arc period (Ta), when the welding current reaches the current value at the time of arc generation, an arc occurs between the base material and a welding wire, and switching takes place from the short circuit period (Ts) to the arc period (Ta); characterized in that the arc period (Ta) includes first, second, third, and fourth periods in this order, in the first period, the welding current is increased up to the first current value with a first inclination (α) to set an arc length of the arc to a first length, in the second period, the welding current is decreased from the first current value to a second current value higher than the pre-arc regeneration current value and lower than the first current value with a second inclination (β) to reduce arc reaction force applied to droplets formed at a leading end of the welding wire, and in the third period, the welding current is increased from the second current value to a third current value lower than the first current value and higher than the second current value with a third inclination (γ) to set the arc length of the arc to a second length in the fourth period wherein in the short circuit period (Ts) and the first, second, and third periods, the welding current is controlled based on a preset current for setting an output of the welding current, in the fourth period, the welding voltage is controlled to be constant based on a preset voltage for setting the output of the welding voltage, in the fourth period, an arc welding control is performed such that the arc length has a constant value, in this case, a value almost equal to the second length. in the short circuit period (Ts), a welding current is increased from a pre-arc regeneration current value lower than a current value at a time of arc generation that is a time of short circuit opening to a first current value in the arc period (Ta), when the welding current reaches the current value at the time of arc generation, an arc occurs between the base material and a welding wire, and switching takes place from the short circuit period (Ts) to the arc period (Ta); characterized in that the arc period (Ta) includes first, second, third, and fourth periods in this order, in the first period, the welding current is increased up to the first current value with a first inclination (α) to set an arc length of the arc to a first length, in the second period, the welding current is decreased from the first current value to a second current value higher than the pre-arc regeneration current value and lower than the first current value with a second inclination (β) to reduce arc reaction force applied to droplets formed at a leading end of the welding wire, and in the third period, the welding current is increased from the second current value to a third current value lower than the first current value and higher than the second current value with a third inclination (γ) to set the arc length of the arc to a second length in the fourth period wherein in the short circuit period (Ts) and the first, second, and third periods, the welding current is controlled based on a preset current for setting an output of the welding current, in the fourth period, the welding voltage is controlled to be constant based on a preset voltage for setting the output of the welding voltage, in the fourth period, an arc welding control is performed such that the arc length has a constant value, in this case, a value almost equal to the second length.