PROBLEM TO BE SOLVED : To provide a mechanism in which a nationwide unification real estate database is constructed to acquire real estate data freely, in a real estate market.SOLUTION : A system provider provides a real estate total cloud service on a WWW server connected to the Internet to promote landlords in a country or management companies committed from the landlords to use the service. Consequently, a nationwide unification real estate database is constructed and businesses in the country relating to real estate business can acquire real estate information freely.