It is an object of the present invention to provide a coloration, which does not damage a contact lens and is not discolored, and to provide an improved technique of manufacturing a contact lens, wherein the contact lens can be marked at the same time as the polymerization of the contact lens in the mold, without troublesome processes. In the present invention, there is adopted, as a coloring composition, a medium which comprises: at least one of monomer components, which constitutes a monomer composition to provide a polymer to form the contact lens; and a predetermined dyestuff. A concave molding surface (28) is roughened by forming a multiplicity of minute recesses by sputtering, before attaching the coloring composition to the concave molding surface; and coloring composition attached to the concave surface (28) is prepolymerized, before the introduction of the monomer mixture to the concave molding surface.