From the research on building activities which have for six years post done in Hiroshima City, the author summarize the characteristic locational trends of the building use, the use of Building, and the size of building according to each zone type, as follows. ? Most buildings in the exclusively residential zone are houses; In the residential zone, there are many apartment houses, factories and community facilities. ? In the neighbourhood commercial zone and the semi-industrial zone, there are many kinds of building; and in the commercial zone, there are mainly commercial and office buildings. ? The higher the permitted limit of floor-area ratio is, the fewer houses are and the more commercial and office buildings are. ? In the zone except industrial zone, an average floor-area ratio of new buildings becomes higher as the permitted limit becomes higher.