Tectonics of the Sangun belt and Sambagawa belt in Southwest Japan, which belong to the metamorphic belt of high-pressure type, have been discussed in this paper. Regarding the Sangun belt, the tectonics of the phases when the original rocks of the Sangun belt were deposited and the Sangun metamorphic field appeared have been analysed. As for the Sambagawa belt, the tectonics of the phases when the Sambagawa metamorphic field was placed under the condition of the highest temperature and then its collapse began have been analysed
