1. A program used for generating a two-dimensional code, the program causing a computer to function as: a data acquisition section which acquires size data of the two-dimensional code, original data to be read from the two-dimensional code, and given binary design data; an unused data region determination section which specifies an unused data region of the two-dimensional code depending on an amount of the original data, based on the size data and the original data; a binary design data conversion section which calculates a bit code by inversely converting the binary design data corresponding to the unused data region based on format information of the two-dimensional code; and a two-dimensional code generation section which converts the calculated bit code and a bit code of the original data based on the format information of the two-dimensional code to generate the two-dimensional code.