This paper clarifies that the military reservation of Imperial Japanese Army has been formed to the space structure of the city in Japan as a nucleus. "Space of Army City" was definite for the space formation of the city. In this paper, Mie Prefecture and Gunma Prefecture are concretely taken up. And, we clarify how the suburban city in Mie Prefecture and the suburban city in Gunma Prefecture have developed by using a military reservation and martial facilities. The urban sociology of Japan has developed as an example the United States urban sociology. Because the United States had won a war, the military reservation was not used except the army. The sociology of Japan has overlooked an important opportunity of the city formation of use of martial facilities for that. It is the one to plan the sociology of a new city space in Japan by seeing the transformation of the space of "Space of Army City" in this paper.