NOVELTY - Fuel reforming apparatus (100) comprises a heat source (10) to generate thermal energy by consuming fuel and producing a heated effluent gas; a reforming reaction unit (30) comprising a space between two pipes that contains a reforming catalyst (31), and adapted to be heated by heat source and generate a reformed gas containing hydrogen through a reforming catalytic reaction of fuel; and a housing (70) encasing the main body. The apparatus also includes a main thermal insulation and an auxiliary thermal insulation, which are made of stainless steel, zirconium, aluminum or ceramic material.    USE - For reforming a polymer electrolyte membrane fuel cell system used for generating electric energy in vehicles, homes, buildings or electronic apparatuses.    ADVANTAGE - Since the reforming reaction unit receives the thermal energy of combustion gas as well as thermal energy directly supplied from the heat source, it can maintain a uniform temperature distribution within a reaction start temperature range required for the reforming reaction throughout the entire region. As a result, the thermal efficiency and performance efficiency of the fuel cell system can be further improved. Since the auxiliary thermal insulation is additionally installed on a local portion of the main thermal insulation, which locally contacts the combustion gas discharged from the heat source, the dissipation of the thermal energy to the external side through the local portion of the main thermal insulation can be prevented, thus reducing the thermal energy loss and preventing the main thermal insulation from being locally damaged.    DETAILED DESCRIPTION - A fuel reforming apparatus comprises:    (1) a main body (50) comprising a first pipe (51) and a second pipe (52)disposed inside the first pipe;    (2) a heat source installed in the second pipe to generate thermal energy by consuming fuel and producing a heated effluent gas in the second pipe;    (3) a reforming reaction unit comprising a space between the two pipes that contains a reforming catalyst, and adapted to be heated by the heat source and generate a reformed gas containing hydrogen through a reforming catalytic reaction of the fuel; and    (4) a housing encasing the main body such as to direct the effluent gas generated from the heat source to flow along and heat an outer circumference of the reforming reaction unit.    The apparatus further includes a flow path (73) and at least one discharging port (75). The housing is made in part from a thermally insulating material, which is a glass fiber.    DESCRIPTION OF DRAWING(S) - The figure is a cross-sectional view of the fuel reforming apparatus.    Heat source (10)    Reforming reaction unit (30)    Reforming catalyst (31)    Main body (50)    First pipe (51)    Second pipe (52)    Housing (70)    Flow path (73)    Discharging port (75)    Fuel reforming apparatus (100)