To provide a heat treatment deformation straightening method which is suitably applicable to an object to be treated consisting of a material necessitating a precipitation hardening heat treatment after executing a solid solution heat treatment.

A deformation generating in the case of heat treating a steel made member is straightened by pressurizing the member W between two temperature adjusting type straightening dies 4A, 4B and deforming by warm press with a desired heat treatment parameter during the last process of hardening by heat treatment or in at least one of a process before or after this process for the member W. According to the deformation straightening method, the heat treatment deformation of the member consisting of an age precipitating material such as e.g. a maltensitic or semi-austenitic precipitation hardening type stainless steel is straightened profiling the shape of the straightening die by the precipitation of a precipitating object, the structural change of a base phase and the transfer of dislocation.