PROBLEM TO BE SOLVED : To enable persons involved to directly perform real estate transaction/ lease transaction with each other by directly performing real estate transaction/ lease transaction on a database via a network between a seller/leaser and a buyer/tenant without the intervention of a real estate broker. SOLUTION : This system is provided with a real estate information providing means 7, with which the terminal device 4 of a seller/leaser side stores and registers real estate information about objects desired to undergo real estate transactions or lease in the database 2 of a server device 1 via a communication network 3, a real estate information retrieving means 6 with which the terminal device 5 of a buyer/tenant side retrieves the real estate information stored in the database 2 via the network 3, a real estate transaction information notifying means 8 with which the buyer/tenant side stores real estate transaction information about a real estate object transaction desired to be bought/rented in the database 2 via the network 3, on the basis of the retrieved real estate information, and a real estate transaction information acquiring means 9 with which the device 4 of the seller/leaser side acquires the real estate transaction information stored in the database 2 via the network 3.