PROBLEM TO BE SOLVED: To provide a dissimilar metal joining method between a steel plate and an aluminum alloy plate, and a dissimilar metal joining joint capable of suppressing preparation of an intermetallic compound on a weld part and capable of improving joint strength, in particular, the joint strength in the separation direction, shock resistance, fatigue strength and corrosion resistance.SOLUTION: When a steel plate 1 and an aluminum plate 2 are joined with each other, as one side electrode 5 of a pair of electrodes 5, 6, a copper electrode, in which a tip diameter D1 of a tip 51 is set to be 6 to 9 mm, formed with a cylindrical recessed part 51a of which the diameter d is 40 to 70% of the tip diameter D1 and the depth h is 0.5 to 2.0 mm is used on a center part of the tip 51, as the other side electrode 6, an electrode of which the tip diameter D2 of a tip 61 is 6 to 16 mm and the tip curvature radius R is 40 to 100 mm is used and, while the electricity is conducted in such a state that the aluminum a
