Abstract: The present invention provides an information sharing apparatus that realizes global information sharing based on partial information which is locally released by communication. The information sharing apparatus includes information management devices each of which has a pipe management system and communicates with each other to transmit information. The pipe management system includes a pipe management part that manages a set of pipes. Each pipe has detailed items and their weights to represent a relationship between two information management devices. The pipe management system further includes a pipe retrieving part that retrieves a pipe matching a request of the user from the set of pipes managed by the pipe management part and a pipe composing part that generates a new pipe by composing retrieved pipes. The pipe management system transmits user's request to the other systems. Thereby pipes matching the request are composed to expand a pipe held by the system that originally transmitted the request.