A data display system (10) and a patent map forming system (20) give evaluation values obtained by a predetermined evaluation axis or an arbitrarily set evaluation value in cooperation with each other, and forms a map sheet (MS) on the basis of the evaluation values. The data display system (10) acquires a first-class identification code such as a publication number from a basic data sheet (DS) obtained by listing bibliographical information or the like of a patent input by a spreadsheet software (22) from an input file, and an identification code conversion unit converts (12) the first-class identification code into a second-class identification code. A patent data server (SV) is directly accessed by the second-class identification code to read an abstract, a representative drawing, all documents, drawings, and the like, serving as detailed data, thereby displaying these data on a display (DP).