Event Detection is important due to be demanded for many kind of application or service about SNW (Sensor Network). But Traditional methods of event detection assume that events are detected in only one SNW. As an environment where many sensors, persons and different kinds of object exist, move and communicate with one another is appearing, it should be taken into account composite event detection in several and heterogeneous SNWs without restricting scale or type of the SNWs. So we propose the application system cooperating among sensor gateway to realize composite event detection in such a environment. In this paper, We present the system that provides user application with services of detecting composite event composed of atomic events that are distributed several heterogeneous SNWs, and discovering a SNW in various regions in order that the application may define atomic events.