The invention relates to an information holding medium which comparatively reduces false recognition and an information processing system. The information processing system 1 includes an information holding medium 2 and an information reading apparatus 3. The information holding medium 2 has two-dimentional arrays of unit data parts 11. In some of the unit data parts 11, a mark 13 for forming a digital code is formed. Mark patterns in an X-direction sequence of two unit data part rows adjacent to each other in a Y-direction are different from each other. The information reading apparatus 3 generates a data string on the basis of a unit signal group formed of a plurality of signals, as a unit, output synchronously from a group of detection units 21 for detecting the mark 13, and recognizesa digital code of the information holding medium 2 on the basis of a group of data strings sequentially obtained from the arrays of unit data parts 11.