The purpose of this study is to investigate the information behavior of the junior high school students in the public library and to find the effectiveness of the behavior analysis using a cognitive work analysis(CWA). Data was collected through a dept interview and an observation method. Results show that the students had four constraints when they searched materials for reports: relevant materials for reports, limitation of materials, opening hours, use possibility. There are three behavior types. A type is that students find materials on the shelf through searching an online catalog, then make a report using reading the materials. B type is that students find materials on the shelf and check out the materials. C type is that students find materials and check out them by library staff help. CWA can be used for the information behavior research on the library space. CWA can, however, apply for space redesign when various researches would be conducted about the information behavior.