In the studied area, through the field and microscopic studies in detail, based upon variations in the mineral assemblage, progressive sequence of mudstone in the studied have been divided into 5 zones, in order of increasing metamorphism; Zone I characterized by chlorite, Zone II by yellow-colored biotite in pleochroism, the Zone III by brown-colored biotite in pleochroism, the Zone IV by cordierite and the Zone V by cordierite replaced into assemblage of chlorite and mica minerals. Distribution of the contact aureole can be regarded to reflect on both the structure of the granite body occurring in a sheet-like body below the land surface, and the movement of actual Otake Fault. The replaced cordierite appear in Zone V can be regarded to formed through hydrothermal reaction in the latest stage of the intrusion process of Hiroshima granite.