INFORMATION CODE, INFORMATION CODE PRODUCING METHOD, INFORMATION CODE READER, AND SYSTEM WHICH USES INFORMATION CODE

An information code producing apparatus produces a free space inside the code region of an information code arranged on a medium such as sheets of paper. The free space is arranged at a position other than specification pattern regions. Data being interpreted, which are expressed by cells, are not recorded in the free space. The free space has a preset size which is larger than that of a single cell. The information code producing apparatus detects the size of this free space by, at least, either selection from a plurality of candidate shapes prepared in advance or input of shape designating information provided from the outside.