To press working a flat metal sheet into a concaved shape, preventing occurrence of wrinkle in the metal sheet surface.

A press working machine includes an upper die set 1 which is comprised of an upper bolster 3, a punch 4 attached under the bolster 3 constituting a press working face, an blank holders 5a, 5b supported movably in vertical direction at both sides of the punch 4 via springs 6a, 6b from the upper bolster 3, and a lower die set 2 which is comprised of a lower bolster 7 and a fixed die 8 placed on the lower bolster 7 constituting the press working face on its upper surface. The bottom 8a of the working face of the die 8 is formed into concavity downward and the bottom 4a of the punch face is formed into convexity downward.