PROBLEM TO BE SOLVED : To form a common transaction market among different objects (real estates, movable properties, services and intangible property rights and the like). SOLUTION : This method consists of a process (step A) for collecting information on real estate (object), a process (step B) for evaluating and managing objective real estate, a process (step C) for preserving and managing the right of object real estate, a process (step D) for purchasing real estate, when the possessor of objective real estate is no longer able to possess the object real estate any more, a process (step E) for issuing a convertible note obtained by making object real estate to be small amount, based on the evaluation and the ranking of real estate and making a reference value per unit to be common, a step (step F) for selling the convertible note, a process (step G) for opening the market of the convertible note on the Internet, a process (step H) for managing the market, a process (step I) for selling and purchasing the convertible note in the market and a process (step J) for conducting transactions in the general market via the convertible note.