To provide a method for joining dissimilar materials capable of easily joining the aluminum based material, made of aluminum or an aluminum alloy, to be welded and the iron based material to be welded with high strength.

In the method for joining dissimilar materials where the aluminum based material 1 to be welded and the iron based material 2 to be welded are welded, the iron based material 2 has an aluminum based coating layer 3 on its surface, the aluminum based material 1 has a flux layer 4 applied at least to the part to be joined with the iron based material 2. Also, in a state where the aluminum based material 1 to be welded is arranged at the side of a torch, and the two materials to be welded are lapped, the two materials to be welded are joined by a melt welding process.