PROBLEM TO BE SOLVED : To provide a transaction support system capable of supporting transactions of real estate or the like effectively.SOLUTION : A transaction support system 1 is used by an information provider 2 who provides information on rental property and an end user 3. The information provider operates an information provider terminal 2 to provide real estate information to the transaction support system 1. This provision of information is performed, through an electronic network, regarding character data and, with a facsimile, regarding a drawing of floor plan or the like. Because the character data and the drawing are separately sent, the transaction support system 1 of this mode of exploitation allocates the drawings corresponding to respective objects (A). In addition, the transaction system 1 extracts the object whose inputted data is not updated over the long term in order to avoid remained data different from a fact (B). In addition, when the end user makes inquiry (C), a number of times of the inquiry is accumulated in the transaction support system 1.