Abstract: A displacement/stress computation unit computes residual stress and deformation by conducting a thermal-elastic-plastic analysis using idealized explicit FEM. A temperature increment is set in magnitude to have a value larger in magnitude than a temperature increment used in a thermal-elastic-plastic analysis using static implicit FEM. Heating is performed for each plurality of blocks according to a heating pattern in which blocks that are not adjacent to one another are simultaneously heated. Each block is heated with a surface heat source having a heat input quantity adjusted with respect to a heat input quantity applied when a moving heat source is used to heat the block.