An arc welding method comprising: welding a base material by a first welding method in a case where a welding parameter related to heat input to the base material is less than a first threshold value, welding the base material by one of the first welding method and a second welding method in a case where the welding parameter is equal to the first threshold value; welding the base material by the second welding method in a case where the welding parameter is less than a second threshold value and is more than the first threshold value; welding the base material by one of the second welding method and a third welding method in a case where the welding parameter is equal to the second threshold value; and welding the base material by the third welding method in a case where the welding parameter is more than the second threshold value, wherein the welding parameter is one of a welding current, a welding voltage, a wire feed speed of a welding wire, and a thickness of the base material, wherein the first welding method is short-circuit welding, wherein the third welding method is pulse welding, wherein the second welding method is a hybrid welding which alternately repeats the short-circuit welding and the pulse welding at a switching period (Tm), and wherein said welding the base material by the second welding method in the case where the welding parameter is less than the second threshold value and is more than the first threshold value comprises welding the base material by changing a ratio between a duration (Ts) in the switching period (Tm) for which the base material is welded by the short-circuit welding and a duration (Tp) in the switching period (Tm) for which the base material is welded by the pulse welding in the switching period (Tm) according to the welding current or the welding voltage. welding a base material by a first welding method in a case where a welding parameter related to heat input to the base material is less than a first threshold value, welding the base material by one of the first welding method and a second welding method in a case where the welding parameter is equal to the first threshold value; welding the base material by the second welding method in a case where the welding parameter is less than a second threshold value and is more than the first threshold value; welding the base material by one of the second welding method and a third welding method in a case where the welding parameter is equal to the second threshold value; and welding the base material by the third welding method in a case where the welding parameter is more than the second threshold value, wherein the welding parameter is one of a welding current, a welding voltage, a wire feed speed of a welding wire, and a thickness of the base material, wherein the first welding method is short-circuit welding, wherein the third welding method is pulse welding, wherein the second welding method is a hybrid welding which alternately repeats the short-circuit welding and the pulse welding at a switching period (Tm), and wherein said welding the base material by the second welding method in the case where the welding parameter is less than the second threshold value and is more than the first threshold value comprises welding the base material by changing a ratio between a duration (Ts) in the switching period (Tm) for which the base material is welded by the short-circuit welding and a duration (Tp) in the switching period (Tm) for which the base material is welded by the pulse welding in the switching period (Tm) according to the welding current or the welding voltage.