PURPOSE: To make it possible to produce part of an unstretchable shaped body from a sheet metal blank by determining a change in volume by a difference between the basic volume of a planar metallic sheet and the basic volume corrected by the deformation of the thin metal blank.

CONSTITUTION: Holes 60, 70 formed in a thin region have an adaptable geometrical shape, such as, for example, an elliptic shape, and are so distributed as to increase toward the flanged ends from a base part in terms of a number or surface area. If an angle region 40 has two ridges delineating an inclined side part 41, the angle region 40 has two hole circuits 60 on the respective side of this inclined side part 41, in other words, in the thin region. Such hole circuits 60, 70 are capable of removing the material of the prescribed amt. corresponding to the excess volume before the deformation. In such a case, the empty spaces formed by the holes 60, 70 are eliminated as the sheet metal blank 10 is formed, by which the deformation of the non-controlled state is eliminated and the maintaining of approximately the specified thickness of the sheet metal blank is made possible.