About twenty years ago the computer was introduced into orthodontic, but not in clinics because it was inconvenient in cost, size, capacity and operation. But recent advances in the technology of electronics have produced a personal computer which is suitable for use in clinics. We have developed useful program for cephalometric Ax, model analysis and patient management. The computer program greatly aided in saving time & effort and performed well in the management & searching for patient data. But further studies about three dimensional analysis, S.T.O. and derivation of automatic treatment planning from analysis are needed.