A terminal device for online real estate transactions, a device, a method, and system for transacting real estate in the network, and a recording medium and an information storage medium for the same are provided to generate, store, and manage real estate transaction contract information with a database by using real estate sale/purchase contract information received from a real estate seller and buyer terminal. The real estate seller terminal(200a) transmits ID confirmation information to a real estate transaction device. A server(100) authenticates and/or confirms ID of the real estate seller based on the received ID confirmation information by linking with an ID authentication server(150), and transmits the real estate seller information and the real estate seller authentication information to a real estate information server(155). The real estate information server extracts or receives the real estate information of the real estate seller matched with the received real estate seller information from the storage medium, and transmits the extracted or received real estate information to the server.