Each of a plurality of polyhedron spaces is defined by a plurality of first vertices. Each of the plurality of first vertices is defined by a plurality of sets of third color data that are defined in the second color space. A color data setting unit sets a plurality of sets of fourth color data that are defined in a first color space in one to one correspondence with the plurality of third color data sets. A second dividing unit divides each of a plurality of polyhedron spaces into a plurality of smaller polyhedron spaces by a division number set for the each polyhedron spaces. Each of the plurality of smaller polyhedron spaces is defined by a plurality of second vertices and the plurality of first vertices. Each of the plurality of second vertices is defined by a plurality of sets of fifth color data defined in the second color space. An interpolation calculation unit calculates a plurality of sets of sixth color data that are defined in the first color space in one to one correspondence with the plurality of second vertices by interpolating the plurality of the fourth color data sets. A conversion table creating unit creates a conversion table based on the fourth color data sets and the sixth color data sets and on the third color data sets and the fifth color data sets.