This paper treats of the Carboniferous fusulinacean zones of the Koyama Limestone in the so-called Kibi-Highland of central Chugoku in western Japan and the paleontological descriptions of sixteen species of Millerella, Ozawainella, Eostaffella, Mediocris, Pseudostaffella, Profusulinella and Endothyra, and the illustrations of nine species of Fusulinaceans and Endothyraceans. In this paper is also given the correlation with the fusulinacean zones of the Akiyoshi Limestone.