A delay tolerant network is built with the use of a plurality of information transfer devices each of which includes: a communication unit to communicate to and from another device within a communication range that is connected to the information transfer device; and a storing unit to store and keeps collected notification information, and each of which holds delay tolerant communication by exchanging the collected and kept notification information with another device when the exchange becomes possible. Each information transfer device includes a control unit to exchange environment information with another information transfer device, and to execute deriving processing an assigned range that is assigned autonomously to its own information transfer device, based on the environment information that is kept by its own information transfer device, through a planarization search processing in which a value is evened out between its own information transfer device and other information transfer devices.