There is provided method for joining dissimilar metals of a steel product and a
light metal product with each other, wherein the
light metal product and a
rivet made of an iron-
base metal are connected with each other beforehand in a previous process preceding
spot welding, and subsequently, the
rivet and the steel product are spot welded with each other. Then, a cavity for use in clinching the
light metal product is formed, and upon the stem of the
rivet is embedded into the light
metal product to penetrate therethrough, light
metal is caused to undergo plastic flow into the cavity of the rivet, for clinching the light
metal product to be thereby clinched with the rivet whereupon
spot welding for forming a weld nugget only within the scope of an interface between the stem of the rivet, and the steel product is carried out. Thus, the present invention can implement the
spot welding between iron—iron similar metals, without a constraint on, and a problem with conditions applicable to the spot
welding and a high joint strength can be obtained owing to the synergistic effect of the spot
welding and connection by clinching of the aluminum
alloy product with the iron-base rivet, added thereto.