Many of Japanese cities rapidly changed their forms and structures through the disaster brought by the last war; and above all, the changes of castle towns were thought to be great enough to make them a particularly noticeable appearance in the history of the city development in Japan.<br>In this paper, Himeji City, one of the typical Japanese castle towns, is taken up and the changing process which Himeji City has undergone since the end of the last war, has been investigated with the results as follows:<br>1) As to the road forms, the narrow winding roads peculiar to a castle town thoroughly disappeared after the war, and modern road network has been constructed throughout the city, improving the traffic condition both inside and outside the city while giving it a new aspect.<br>2) At the same time, the old city plannings inherited from old feudalistic times, has collapsed; and there arose the necessity of improving the mode of administration, giving up the old town-unit system.<br>3) In Himeji City, at the beginning of Meiji Era, an army division was stationed and, therefore, the central part of the city was monopolized by military institutions. After Japan was defeated in the last war, however, the army disappeared and the central part of the city was reborn as a center of government, public services, city sanitation, culture and education.<br>4) Teramachi (Temple Quarter) was one of the quarters which gave peculiar aspects to Himeji Castle Town, but now it brings about its remarkable decline as a result of the war, disaster and the following new city-reconstruction plan which includes removal of cemetery to the suburbs.<br>5) In old Himeji, the institutes of finance and amusement centers had tended to be concentrated and prospered along the Saikokukaido and Miyuki-dori. But after the war, the commercial area has shown the tendency of regional division as a result of the appearance of newly opened Otemae-dori according to the reconstruction plan.<br>6) In Himeji, the development of industries was the motive power for the development of the urbanised area but after the war, not a few factories in the old city center were abolished and those factory sites have been used for the residential areas in many places.<br>7) Himeji lost about half of the houses due to the war disaster but reconstructed them again rather rapidly. Nowadays it is remarkable that civilian, not governmental, residences are made annually in great number, and recently there is a tendency that the residential area is spreading to the surrounding farm lands and mountainous regions of the city.