Abstract: A two-dimensional code publishing program that provides display of beautiful two-dimensional codes with homogeneity and a high sense of design, and a two-dimensional code decoding program that decodes bit strings expressed as two-dimensional codes in various situations. In a display of cells having a color with a low visibility against the blank area surrounding the two-dimensional code, a contrast is set between the gradation of the color component having a gradation close to that of the blank area and/or in a display of cells having a color with a high visibility against the blank area surrounding the two-dimensional code, the contrast is reduced between the gradation of the color component having a gradation far from that of the blank area.