PROBLEM TO BE SOLVED : To provide an on-line real estate retrieval information collective management system for collectively registering and managing information being an object for retrieval in a plurality of real estates retrieval sites.SOLUTION : The system is provided with an information registrant terminal, a certifying means for certifying the information registrant on a server side when access is given from the information registrant, a real estate information registration means registering real estate information transmitted from the information registrant terminal in a server, a real estate information data base storing registered information on a real estate and a real estate information converting means converting information stored in the real estate information data base into a data system for retrieving it at the real estate retrieval site. A means for permitting a real estate information supplier cooperated with the server to register information registered in the real estate retrieval site for displaying and displaying registered real estate information on online by the real estate information registration means and restricting the update/change/ deletion of information which is previously set and registered is installed in the system.