An arc start control method being characterized by: step 1 for driving a wire feed motor to start advancing a welding wire; step 2 for determining that a distal end of the welding wire contacts a base material due to the advance of the welding wire and short circuit is caused between the welding wire and the base material; step 3 for detecting a feed torque value of the wire feed motor as a short circuit determination torque value at the time of the determination of short circuit; and characterised by: step 4 for starting retracting the welding wire and separating the distal end of the welding wire from the base material without generating an arc, and returning to step 1 if the short circuit determination torque value is a reference torque value or greater; step 5 for starting retracting the welding wire and separating the distal end of the welding wire from the base material and generating an initial arc between the welding wire and the base material if the short circuit determination torque value which is detected in the step 3 after the step 4 is performed is smaller than the reference torque value; step 6 for continuing retracting the welding wire while maintaining the initial arc to elongate an arc length; and step 7 for stopping retracting the welding wire and starting advance of the welding wire to change a state of the arc from the initial arc to a steady arc. step 1 for driving a wire feed motor to start advancing a welding wire; step 2 for determining that a distal end of the welding wire contacts a base material due to the advance of the welding wire and short circuit is caused between the welding wire and the base material; step 3 for detecting a feed torque value of the wire feed motor as a short circuit determination torque value at the time of the determination of short circuit; and characterised by: step 4 for starting retracting the welding wire and separating the distal end of the welding wire from the base material without generating an arc, and returning to step 1 if the short circuit determination torque value is a reference torque value or greater; step 5 for starting retracting the welding wire and separating the distal end of the welding wire from the base material and generating an initial arc between the welding wire and the base material if the short circuit determination torque value which is detected in the step 3 after the step 4 is performed is smaller than the reference torque value; step 6 for continuing retracting the welding wire while maintaining the initial arc to elongate an arc length; and step 7 for stopping retracting the welding wire and starting advance of the welding wire to change a state of the arc from the initial arc to a steady arc. step 4 for starting retracting the welding wire and separating the distal end of the welding wire from the base material without generating an arc, and returning to step 1 if the short circuit determination torque value is a reference torque value or greater; step 5 for starting retracting the welding wire and separating the distal end of the welding wire from the base material and generating an initial arc between the welding wire and the base material if the short circuit determination torque value which is detected in the step 3 after the step 4 is performed is smaller than the reference torque value; step 6 for continuing retracting the welding wire while maintaining the initial arc to elongate an arc length; and step 7 for stopping retracting the welding wire and starting advance of the welding wire to change a state of the arc from the initial arc to a steady arc.