The “eclogitic rock” has been found from an area of migmatitic gneisses in the Hida Metamorphic Belt, central Japan. The rock is mainly composed of almandinous garnet, augitic clinopyroxene and quartz. Field occurrence does not show any tectonic discontinuity between the fusiform mass of the “eclogitic rock” and the surrounding gneisses whicshow the assemblage of the amphibolite facies. As the result of the petrochemical studieson the rock and its constituent minerals, it is well be said that this rock is derived from some FeO-rich rock under the metamorphic condition of the granulitic facies, which wouldrepresent the older metamorphic phase before the PermoTiassic regional metamorphism of the plateau.