PROBLEM TO BE SOLVED : To efficiently perform negotiation up to the conclusion of agreement by making the negotiation unitary in real estate transactions such as home buying among respective parties concerned including an actually related financial institution, etc.SOLUTION : A negotiation item inputting part 61 receives an input of a series of negotiation items in regard to a transaction from the respective concerned, and the inputted negotiation items are stored in a negotiation item database 63 in each different item. An item presenting part 62 presents a negotiation item read from the database 63 only to a predetermined specific party concerned between the respective parties concerned related to the transaction according to disclosure range data read from a disclosure range database 64.