This study aims to develop an information sharing GIS, specially tailored to the efficient accumulation of regional knowledge within regions on the city, town, and village spatial scale. The information sharing GIS is a geographical information system which integrates a Web-GIS, an SNS (Social Networking Service), and a Wiki into a single system. The information sharing GIS uses a design which ameliorates the following three constraints such as time constraints, spatial constraints and continuous operation related constraints, making it possible to design systems in accordance with target cases. After operating the information sharing GIS to accumulate regional knowledge about security information for about one month in the local communities of Chofu City and Mitaka City in Tokyo, the system was evaluated based on the results of a questionnaire survey to users in order to identify improvements.