In recent society, global warming causes emission of carbon dioxide and raises remarkable issues. This study investigated the quantities of carbon dioxide on reinforced concrete buildings in the Tokyo metropolitan area during the manufacturing and transportation of materials to be used. Moreover, those quantities were compared between a basic RC building and a building using scallop shells. Scallop shells can fix carbon. As a result of calculations, scallop shells can contribute to the reduction total carbon dioxide quantities because they can store carbon dioxide on their own, and achieve the carbon-neutral theory, which states that quantities of emission and absorption of carbon dioxide are equal in the life cycle.