Abstract: A consumable electrode arc-welding machine comprising an arc resistance calculating part that calculates an arc resistance from a welding current and a welding voltage to develop an arc resistance signal, wherein the welding current and welding voltage are controlled by a short-circuit waveform control signal and an arc waveform control signal that vary in accordance with the arc resistance signal. In this way, the spatter control and the arc stability can be achieved. During an arc period, if the arc resistance signal exhibits a level greater than a predetermined level for a predetermined period, a constant current control signal is developed to perform a constant current control of the welding current by use of a predetermined current value that is higher than the current value developed during the development of the arc waveform control signal, thereby preventing the arc from going off.