PURPOSE : A real estate contract confirmation and a real estate cheating blocking system using internet for performing a contract mediation process until the completion of registration of leaseholder rights are provided to make a contract of high reliability by supplying contract information to a government office.CONSTITUTION : A web server(20) mediates a contract through a seller computer(30) and a buyer computer(40). A document keeping company processes the request of the web server. A financial institution is connected to internet network and implements deposit and withdrawal of the charge related to internet network. A real estate business-handling administrative institution issues the subject document related to the contract.COPYRIGHT KIPO 2011