NOVELTY - A fuel reformer (100) comprises a main heat source including an oxidation catalyst to generate thermal energy at 600-700degreesC through an oxidation reaction of a fuel using the oxidation catalyst; an auxiliary heat source (20), including a torch (21) to ignite and burn the gaseous fuel, to preheat the oxidation catalyst to 150-300degreesC; and a reforming reaction unit including a reforming catalyst (31) in a region of a space between the pipes and adapted to generate a reforming gas containing hydrogen through the reforming reaction of the fuel using the reforming catalyst.    USE - For generating thermal energy in fuel cell system.    ADVANTAGE - Since the oxidation catalyst is preheated by igniting and burning the fuel only when the fuel reformer is initially driven, the initial driving time of the fuel reformer is decreased, thus improving energy efficiency of the fuel reformer, and the durability of the auxiliary heat source against a flame is improved, thus increasing the lifetime of the fuel reformer.    DETAILED DESCRIPTION - A fuel reformer comprises:    (a) a first pipe (51);    (b) a second pipe (52) disposed in the first pipe;    (c) a main heat source including an oxidation catalyst in the second pipe to generate thermal energy at 600-700degreesC through an oxidation reaction of a fuel using the oxidation catalyst;    (d) an auxiliary heat source, including a torch connected to the second pipe to ignite and burn the gaseous fuel, to preheat the oxidation catalyst to 150-300degreesC; and    (e) a reforming reaction unit including a reforming catalyst in a region of a space between the first and second pipes and adapted to generate a reforming gas containing hydrogen through the reforming reaction of the fuel using the reforming catalyst by using the thermal energy generated by the main heat source.    DESCRIPTION OF DRAWING(S) - The figure is a perspective view illustrating a fuel reformer.    Auxiliary heat source (20)    Torch (21)    Reforming catalyst (31)    Reactor body (50)    First pipe (51)    Second pipe (52)    Fuel reformer (100)