NOVELTY - The fuel cell process apparatus useful in a fuel cell system, comprises a first desulfurizer (110) including an adsorbent that adsorbs sulfuric components in the fuel, a second desulfurizer (120) connected to the first desulfurizer and including a desulfurizing catalyst that causes an exothermic reaction with the sulfuric components in the fuel, a reformer (130) connected to the second desulfurizer and reforming the fuel into a reforming gas containing hydrogen, and a case body (101) containing the second desulfurizer and the reformer. The first desulfurizer is disposed outside the case body.    USE - The fuel cell process apparatus is useful in a fuel cell system (claimed).    ADVANTAGE - The fuel cell process apparatus is capable of efficiently, economically and rapidly removing the sulfuric components in the fuel, has improved stability and durability, and requires less maintenance.    DETAILED DESCRIPTION - The fuel cell process apparatus useful in a fuel cell system, comprises a first desulfurizer (110) including an adsorbent that adsorbs sulfuric components in the fuel, a second desulfurizer (120) connected to the first desulfurizer and including a desulfurizing catalyst that causes an exothermic reaction with the sulfuric components in the fuel, a reformer (130) connected to the second desulfurizer and reforming the fuel into a reforming gas containing hydrogen, and a case body (101) containing the second desulfurizer and the reformer. The first desulfurizer is disposed outside the case body. The first and second desulfurizer and the reformer are designed such that the fuel for a fuel cell system passes through the desulfurizers and the reformer. A first pipe is connected to the first desulfurizer such that the fuel flows into the first desulfurizer from outside. The first and second desulfurizers are connected via a second pipe. The first and second pipes are connected via a third pipe such that the fuel bypasses the first desulfurizer. A diverter valve that converts the inflow path of the fuel is disposed at the point where the first pipe and the third pipe are connected. The second desulfurizer and the reformer are connected via a fourth pipe. The second and fourth pipes are connected via a fifth pipe such that the fuel bypasses the second desulfurizer. A first solenoid valve is disposed at the second pipe for selectively controlling the flow of the fuel. A second solenoid valve is disposed at the fifth pipe, and selectively controls the flow of the fuel. The operation of the second solenoid valve is related to the first solenoid valve. The second desulfurizer transforms the sulfuric components into hydrogen sulfide and causes the exothermic reaction involving the desulfurizing catalyst. An INDEPENDENT CLAIM is included for a fuel cell system.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a fuel process apparatus.    Case body (101)    First desulfurizer (110)    Second desulfurizer (120)    Reformer (130)    Carbon monoxide reducer (140)    Carbon monoxide remover. (150)