To provide joining structure for metallic members, and punching member and fixing structure used for joining the metallic members and a method of joining the metallic members, wherein the joining accuracy and joining strength can be easily secured without using high-cost method such as welding and without projecting the end part of a joining project of the metallic member on one side from the metallic member on the other side.

In the structure for joining the metallic members, joining projections 11d provided on a frame member 11 and through-holes 12c provided on an L-shape member 12 are joined by making the joining projections 11d plastically deform in a state where they are fit, the frame member 11 and the L-shape member 12 are joined by pressing the structural walls of the through-holes 12c from the inside with the plastically deformed joining projections 11d and the plastically deformed joining projections 11d are nested into the inside of the through-holes 12c.