There is provided a surface shape defect generating region estimating method for estimating a generating region of a surface shape defect of a deformation-processed product obtained by performing deformation processing with respect to a workpiece, the method including: a first stress distribution obtaining process of obtaining first stress distribution σ(T1); a second stress distribution obtaining process of obtaining a second stress distribution σ(T2); a comparative stress distribution obtaining process of obtaining comparative stress distribution σ(T1, T2); a division comparative stress distribution obtaining process of obtaining division comparative stress distribution σDIV(T1, T2); and a surface shape defect generating region estimating process of estimating whether or not each of the divided regions DK is a generating region of the surface shape defect.