To provide a sheet metal working method for forming a corrugated portion and a plurality of positioning holes with high accuracy in a metal sheet, and also executing the post-process working with excellent accuracy.

In the sheet metal working method, a corrugated portion w having a wave-like shape is formed by the press bending on the metal sheet 2 using a common press die, and at the same time, a plurality of positioning holes p, q are blanked by the press blanking. A formed metal sheet 2 is worked and formed, in which the plurality of holes p, q are arrayed in parallel with the corrugated portion w with the predetermined distance apart therefrom.