The abnormality determination and estimation device (200a) estimates the presence or absence of an abnormality of the product of plastic working with respect to an elastic wave in processing of a non-defective product, based on a first elastic wave A1 that is an elastic wave generated in a processing step immediately before an upper die comes into contact with a lower die after the beginning of plastic working, a second elastic wave A2 that is an elastic wave generated in a processing step when the upper die comes into contact with the lower die, and a third elastic wave A3 that is an elastic wave generated in a processing step after the upper die comes into contact with the lower die. This makes it possible to improve the precision of abnormality detection and discriminate the abnormalities.