To have convenient and highly precise prediction of the shape of a human body after a treatment by calculation processing that includes extracting a feature vector Fnew from face data of a patient as an evaluation subject, selecting a plurality of case patients having feature vectors Fpre(i), extracted from the face data of a plurality of previous patients, obtaining pre-orthodontic facial shape models Hpre(i) and a post-orthodontic facial shape models Hpost(i) in which the faces of the selected previous case patients before and after a treatment have been normalized, obtaining a facial shape model Hnew, and obtaining a three-dimensional predicted facial shape model Hprd, by modifying the facial shape model Hnew of the patient as an evaluation subject, using a vector average difference AVEpost−AVEpre between the pre-treatment and post-treatment facial shape models.