PROBLEM TO BE SOLVED: To provide a joining material whose lightening can be attained while maintaining its strength and rigidity, to provide a production method therefor, to provide a structure of a traffic transportation means, and to provide a structure of a railway vehicle.
SOLUTION: The joining material 3 is used for a structure of a traffic transportation means such as a railway vehicle. The joining material 3 is a clad plate with a sandwich structure obtained by joining a metal 3a and a metal 3b with an adhesive agent layer 3c. The metal 3a is an alloy bulk material such as an aluminum alloy, a titanium alloy and stainless steel. As the aluminum alloy, the one for elongation is preferable, and a heat treatment type alloy such as a 6,000 series aluminum alloy which has excellent strength and corrosion resistance and can obtain prescribed strength by age hardening is particularly preferable. The metal 3b is a magnesium alloy, and is a magnesium alloy extruded material subjected to extrusion working. As the adhesive agent layer 3c, a powerful adhesive such as an epoxy adhesive is preferable in the case heating treatment is performed after coating.