To find effective solutions to social problems, it is desirable to grasp the structure of the problems. It is recognized that no inter-disciplinary technique has been established att this moment. In this article, we attemptt to build a 3D visual exploration tool to assist the users in grasping the structure of a target. social problem subjectively and thus finding a promising solution. The tool. named "Social Problem Viewer", relies primarily on the Conetrees-based representation of the knowledge obtained from analyzing pastt cases to facilitate their organizing and exhibiting potential solutions to an unknown social problem. Social Problem Viewer is available through the Internet, and suitable for collaborative usage. The feasibility of the present Social Problem Viewer is illustrated with an application to the earthquake disaster prevention problem.