Purpose: Some librarians and researchers in the field of Library and Information Science predict that library buildings will disappear in the near future as all library materials become available on the Internet. On the other hand, there are others who are reevaluating the role of traditional libraries as a "place" for studying or reading in the Internet age. In Japan, Learning Commons has become popular as a result of the reevaluation of "the library as place", unfortunately, however, it is insufficient to discuss the theoretical aspects of providing Learning Commons in campuses, and therefore its purpose and functionality remain unclear. Clarifying the concept of "the library as place" is considered to be a first step for solving the problem. This paper examines empirically the actual situation of library use as "place" in order to discuss this concept. Methods and Results: At Yokohama National University Central Library in Japan, users' staying place, belongings and behavior were investigated by unobtrusive observation during three days (June 23-25th, 2009). The library space was divided into 30 areas, and investigators observed library users in each area. In total, 9,610 users were investigated. The results showed that 1) the library is used as a learning space for undergraduate students, 2) the personal computers in the library are heavily used, 3) that there are various ways of using the library facilities. The observational investigation method used in this study is effective for examining effectively library use, but it can not clarify users' cognitive aspects; these may be measured by questionnaires.