The purpose of this study is, focusing on the "multipurpose common space", to consider arrangements of rooms in order to reveal the openness of "campus architecture". First, the multipurpose common space and adjacent rooms were grasped as a "common space continuum" and organized as "basic model" and "hierarchized model". Secondly, the composition of building which combined them were considered to reveal the openness of "campus architecture" such as the composition which has several same kinds of "basic models" and the one where a single "hierarchized model" emerges on the whole elevation surface and faces a place like a square.