To obtain continuous spot weldability and appearance quality in a welded part which is equivalent to a steal sheet by permitting to keep a contacting end-diameter of the electrode constant and permitting to keep a current density constant during welding, in the continuous spots at the time of a resistance spot welding to Al alloy.

In the range of a temp. near the end part of the electrode during passing a welding current, a high temp. hardness characteristic fitting into a softening characteristic of Al alloy material to be welded i.e., a soften characteristic within a specified temp. zone is provided to the electrode 1. Specifically, with respect to the electrode 1 used in the resistance spot welding to the Al alloy material to be welded, the electrode is composed of the material having the high temp. hardness characteristic which is softened from ≥Hv80 to ≤Hv30 in the Vickers hardness at 200°C-400°C so as to be ≥971ACS% in the electric conductivity of the electrode, ≥Hv80 at ≤200°C and ≤Hv30 at ≥400°C in the Vickers hardness. The resistance spot welding is performed by using this electrode for the resistance spot welding to the Al material to be welded.