1. A two-dimensional code generation device, comprising: a white point determiner to determine a white point in an environment to output a two-dimensional code; a threshold acquirer to acquire a threshold of lightness used by a reading device for reading multiple cells in binary, the threshold being represented in a device-independent color space that is based on the white point determined by the white point determiner, and the threshold varying depending on lightness that corresponds to a white color determined by the white point; a two-dimensional code generator to generate the two-dimensional code expressing information by a distribution pattern of multiple cell dots formed by coloring the multiple cells in a color of lightness equal to or higher than the threshold acquired by the threshold acquirer and in a color of lightness lower than the threshold, a logo image acquirer to acquire a logo image; and a lightness acquirer to, when the logo image acquired by the logo image acquirer is represented in a device-dependent color space, convert the acquired logo image into a logo image represented in the device-independent color space and acquiring lightness of each part within the logo image represented in the device-independent color space, wherein the two-dimensional code generator generates as the two-dimensional code a logo-included two-dimensional code on which the logo image is superimposed by superimposing cell dots colored in a color of lightness lower than the threshold on parts of the logo image that are superimposed on cells that are to be colored in a color of lightness lower than the threshold among the multiple cells and of which the lightness acquired by the lightness acquirer is equal to or higher than the threshold, and superimposing cell dots colored in a color of lightness equal to or higher than the threshold on parts of the logo image that are superimposed on cells that are to be colored in a color of lightness equal to or higher than the threshold among the multiple cells and of which the lightness acquired by the lightness acquirer is lower than the threshold.