In this arc welding method, when a welding parameter related to heat input to base material is less than a first threshold value, the base material is welded by a first welding method. When the welding parameter is less than a second threshold value and greater than the first threshold value, the base material is welded by a second welding method. When the welding parameter is greater than the second threshold value, the base material is welded by a third welding method. With this arc welding method, by adjusting welding conditions regardless of the thickness of the base material, a welding method suited to the thickness of the base material is selected, and thus it is possible to perform welding with little spattering and no burn through of the base material.