PROBLEM TO BE SOLVED : To provide an information processing system for allowing a buying-selling and leasing enterprise, a real estate intermediary, and a third beneficiary in real estate transactions to unitarily execute a request for buying and selling real estate and lease transactions, a bid, disclosure, an offer procedure, and contract content confirmation including browsing of information by using an information distributing program.SOLUTION : A requester, the intermediary, and the third beneficiary can simultaneously gather information from an information integrated circuit S06 providing corresponding property information and transaction information when using the collection and distribution of unutilized real estate property information and executing land and building real estate buying-selling transactions and real estate lease contract transactions, and can shorten the unutilized period by promoting the circulation and use of unutilized real estate by creating many chances of real estate property transactions by exempting a real estate transaction commission of the third beneficiary. This transaction system is an input-output processing to the program of an information collecting-distributing system in the real estate transactions, and particularly makes an accounting burden onto the third beneficiary of the real estate transaction intermediary commission free.