In the process of target stamping for fracture judgment, an acquisition unit acquires, as target data for fracture judgment, strain of a target die to be measured over the duration from the start time of stamping measured by strain measuring units to the finishing time of stamping, and also acquires production conditions typically by measurement. An extraction unit extracts the reference data, which gives the minimum total of differences between the production conditions of the reference data and the production conditions of the target data for fracture judgment, as the comparative data. A judging unit compares strain in the comparative data extracted by the extraction unit and strain in the target data for fracture judgment, and judges occurrence of a crack in a stamped product, if the maximum value of the difference is not smaller than a predetermined value.