NOVELTY - A reformer (30) of a fuel cell system comprises a main body (31) in which several reaction sections (35) for generating hydrogen from hydrogen-containing fuel are integrally formed; and a heating section (37) which is disposed in contact with the main body and which supplies a different amount of thermal energy to each of the several reaction sections.    USE - For a fuel cell system useful for generating electricity (claimed).    ADVANTAGE - The reformer has improved performance and a simple structure. Thus, making the entire fuel system compact and enhancing the efficiency of the entire fuel system. The heating section has a structure that different amounts of thermal energy are supplied to the respective reaction sections by making the resistance wire pattern different in gap, thickness, or width.    DETAILED DESCRIPTION - The main body defines an inner space that is divided into several spaces, which define the several reaction sections, a reformer inlet (32) and a reformer outlet (33). The heating section comprises a resistance wire (38) of a coil shape wound around the outer circumferential surface of the main body in a predetermined number of windings, where the number of windings around the outer circumferential surface of the main body corresponding to a particular reaction section is different from the numbers of windings corresponding to the other of the reaction sections. The several reaction sections includes a reforming reaction section for generating hydrogen gas from the hydrogen-containing fuel and at least one carbon-monoxide reducing section for reducing the concentration of carbon monoxide contained in the hydrogen gas, and the number of windings of the resistance wire in an area corresponding to the reforming reaction section is greater than the number of windings corresponding to the carbon-monoxide reducing section. The divided spaces within the inner space of the main body are divided by barrier(s). The reformer further comprises a heat-insulating jacket (39) surrounding the main body.    DESCRIPTION OF DRAWING(S) - The figure shows coupled cross-sectional view illustrating the reformer.    reformer (30)    main body (31)    reformer inlet (32)    reformer outlet (33)    reaction sections (35)    heating section (37)    resistance wire (38)    heat-insulating jacket. (39)