A method of arc-welding hot dip Zn-based alloy coated steel sheets (1, 1'), each of which includes a coating layer that contains Zn as a main component and that contains Al at a concentration of 1.0 % by mass to 22.0 % by mass; - each of the hot dip Zn-based alloy coated steel sheets (1, 1') having a coating weight W of 15 g/m 2 to 250 g/m 2 per surfacer; - the hot dip Zn-based alloy coated steel sheets (1, 1') being arc-welded in such a way that (a) a current waveform formed by a welding current is a pulsed current waveform in which (i) a peak current and a base current alternate with each other at a pulse period of 1 ms to 50 ms and (ii) an average welding current is 100 A to 350 A and (b) an average welding voltage is 20 V to 35 V; - the hot dip Zn-based alloy coated steel sheets (1, 1') being arc-welded by using an Ar-CO 2 mixed gas as a shielding gas, so that transfer of a small droplet, that is, spray transfer is carried out; - the coating layer included in the each of the hot dip Zn-based alloy coated steel sheets (1, 1') further contains at least one selected from the group consisting of Mg, Ti, B, Si, and Fe, the coating layer containing - the Mg at a concentration of 0.05 % by mass to 10.0 % by mass, - the Ti at a concentration of 0.002 % by mass to 0.10 % by mass, - the B at a concentration of 0.001 % by mass to 0.05 % by mass, - the Si at a concentration of 0 % by mass to 2.0 % by mass, and/or - the Fe at a concentration of 0 % by mass to 2.5 % by mass; and - the coating weight W (g/m 2) of the each of the hot dip Zn-based alloy coated steel sheets (1, 1') and an Al concentration C Al (% by mass) of the coating layer included in the each of the hot dip Zn-based alloy coated steel sheets satisfying the following expression: 0.0085 W + 0.87 ≤ C AI ≤ 22 - each of the hot dip Zn-based alloy coated steel sheets (1, 1') having a coating weight W of 15 g/m 2 to 250 g/m 2 per surfacer; - the hot dip Zn-based alloy coated steel sheets (1, 1') being arc-welded in such a way that (a) a current waveform formed by a welding current is a pulsed current waveform in which (i) a peak current and a base current alternate with each other at a pulse period of 1 ms to 50 ms and (ii) an average welding current is 100 A to 350 A and (b) an average welding voltage is 20 V to 35 V; (a) a current waveform formed by a welding current is a pulsed current waveform in which (i) a peak current and a base current alternate with each other at a pulse period of 1 ms to 50 ms and (ii) an average welding current is 100 A to 350 A and (b) an average welding voltage is 20 V to 35 V; - the hot dip Zn-based alloy coated steel sheets (1, 1') being arc-welded by using an Ar-CO 2 mixed gas as a shielding gas, so that transfer of a small droplet, that is, spray transfer is carried out; - the coating layer included in the each of the hot dip Zn-based alloy coated steel sheets (1, 1') further contains at least one selected from the group consisting of Mg, Ti, B, Si, and Fe, the coating layer containing - the Mg at a concentration of 0.05 % by mass to 10.0 % by mass, - the Ti at a concentration of 0.002 % by mass to 0.10 % by mass, - the B at a concentration of 0.001 % by mass to 0.05 % by mass, - the Si at a concentration of 0 % by mass to 2.0 % by mass, and/or - the Fe at a concentration of 0 % by mass to 2.5 % by mass; and - the Mg at a concentration of 0.05 % by mass to 10.0 % by mass, - the Ti at a concentration of 0.002 % by mass to 0.10 % by mass, - the B at a concentration of 0.001 % by mass to 0.05 % by mass, - the Si at a concentration of 0 % by mass to 2.0 % by mass, and/or - the Fe at a concentration of 0 % by mass to 2.5 % by mass; and - the coating weight W (g/m 2) of the each of the hot dip Zn-based alloy coated steel sheets (1, 1') and an Al concentration C Al (% by mass) of the coating layer included in the each of the hot dip Zn-based alloy coated steel sheets satisfying the following expression: 0.0085 W + 0.87 ≤ C AI ≤ 22