PROBLEM TO BE SOLVED : To provide an evaluation information management system for presenting evaluation information on the lessor of lease property such as a real estate to a lessee. SOLUTION : A data management system 1 receives lease property information from lessor terminals 31, 32and 3kthrough the Internet NW, and receives lease contract information from a lessee terminal 2 through the Internet NW, and generates evaluation information showing the degree of advantage of a lessee Y for lease contract conditions presented from lessors X1, X2 and Xk with objective figures as a deviation value for each lessor X1, X2 and Xk on the basis of the lease property information and the lease contract information, and opens it on a Web site on the Internet NW. Thus, it is possible even for a new customer Q to easily decide a superior real estate. Also, figures as evaluation values always fluctuate in terms of numerical features as a deviation value, so that it is possible to prevent such an easy decision that the property handled by the agent having a large number of transaction results is superior. COPYRIGHT : (C)2007, JPO&INPIT