A method of controlling pulse arc welding, comprising: providing a pulse arc welding device that welds an object with a welding wire; controlling the pulse arc welding device so as to weld the object by generating an arc between the welding wire and the object by causing a welding current to flow through the welding wire while feeding the welding wire to the object at a feeding speed such that the welding current alternately repeats a peak current period in which the welding current is a peak current and a base current period in which the welding current is a base current smaller than the peak current; and being characterized by: controlling the feeding speed in the following way, so as to keep an arc length of the arc to be constant: setting the feeding speed to a first feeding speed in the base current period; setting the feeding speed to a second feeding speed in the peak current period, the second feeding speed being larger than the first feeding speed and corresponding to the first feeding speed; starting to increase the feeding speed from the first feeding speed toward the second feeding speed simultaneously when the welding current starts to rise from the base current toward the peak current while transferring from the base current period to the peak current period in a pulse-rising period (IPRT); starting to decrease the feeding speed from the second feeding speed toward the first feeding speed simultaneously when the welding current starts to fall from the peak current toward the base current while transferring from the peak current period to the base current period in a pulse-falling period (IPFT). providing a pulse arc welding device that welds an object with a welding wire; controlling the pulse arc welding device so as to weld the object by generating an arc between the welding wire and the object by causing a welding current to flow through the welding wire while feeding the welding wire to the object at a feeding speed such that the welding current alternately repeats a peak current period in which the welding current is a peak current and a base current period in which the welding current is a base current smaller than the peak current; and being characterized by: controlling the feeding speed in the following way, so as to keep an arc length of the arc to be constant: setting the feeding speed to a first feeding speed in the base current period; setting the feeding speed to a second feeding speed in the peak current period, the second feeding speed being larger than the first feeding speed and corresponding to the first feeding speed; starting to increase the feeding speed from the first feeding speed toward the second feeding speed simultaneously when the welding current starts to rise from the base current toward the peak current while transferring from the base current period to the peak current period in a pulse-rising period (IPRT); starting to decrease the feeding speed from the second feeding speed toward the first feeding speed simultaneously when the welding current starts to fall from the peak current toward the base current while transferring from the peak current period to the base current period in a pulse-falling period (IPFT). setting the feeding speed to a first feeding speed in the base current period; setting the feeding speed to a second feeding speed in the peak current period, the second feeding speed being larger than the first feeding speed and corresponding to the first feeding speed; starting to increase the feeding speed from the first feeding speed toward the second feeding speed simultaneously when the welding current starts to rise from the base current toward the peak current while transferring from the base current period to the peak current period in a pulse-rising period (IPRT); starting to decrease the feeding speed from the second feeding speed toward the first feeding speed simultaneously when the welding current starts to fall from the peak current toward the base current while transferring from the peak current period to the base current period in a pulse-falling period (IPFT).