The aim of this study is to clarify the spatial composition of open spaces in urban commercial buildings. As a case study 91 commercial buildings of central Tokyo are analyzed. In high-dense city such as Tokyo, open spaces of commercial buildings are widely recognized as main private open spaces. Focusing on formation and accessibility of three-categorized open spaces as outside, semi-outside, and inside-common spaces, 13 types of spatial compositions are identified. In commercial high-dense city it is possible to draw not only customers but also the general public from street into commercial buildings. Therefore, this paper examines continuity between street and their open spaces from connection between aforesaid spatial compositions and layout of shop entrances.
