A method for joining metal materials, which joins a first member with at least a joining face made of Metal A, the Metal A being mainly composed of at least one selected from the group consisting of Al, Cu, Ag and Au, to a second member with at least a joining face made of Metal B, the Metal B being mainly composed of at least one selected from the group consisting of Al Cu, Ag and Au, includes interposing an insert between the joining faces of the first and second members, wherein the insert contains Zn as a metal capable of causing an eutectic reaction with at least one metal except for Au in Metal A as well as at least one metal except for Au in Metal B.