This paper describes an approach to detect the entrance of building with hopeful that it will be applied for autonomous navigation robot. The entrance is an important component which connects internal and external environments of building. We focus on the method of entrance detection using multiple cues. The information of entrance characteristics such as relative height and position on the building is considered. We adopt the probabilistic model for entrance detection by defining the likelihood of various features for entrance hypotheses. To do so we first detect building's surfaces. Secondly, wall region and windows are extracted. The remained regions except the wall region and windows are considered as candidate of entrance. Finally, the entrance is identified by its probabilistic model.