Openness to outside is one of the most critical advantages for high-rise buildings. However, the effect of openness can be decreased if it is blocked by other high-rise buildings, especially built within the building complex of commercial district. The purpose of this study is to identify the horizontal openness of high-rise residential buildings by comparing 3 different cases of building arrangement type. A new method of evaluation has been introduced on the basis of distance to measure the openness including the matter of securing privacy. As a result of this study, comparative analysis was possible and relatively plentiful results of analysis could be drawn out. Through the process of analysis, this study set the evaluation indicators suitable to the analysis of openness of unit households. Thereby, the results of this study are expected to be used as useful basic data in planning high-rise mixed-use buildings.