NOVELTY - Reforming apparatus (10) comprises: a reformer (12) that generates reformed gas from raw fuel; a shift reactor (14) that reduces carbon monoxide present in the reformed gas; a selective oxidation unit (16) that reduces the carbon monoxide present in the reformed gas; a reforming reaction tube (18) that houses linearly the reformer, shift reactor and selective oxidation unit; a combustion means which produces combustion exhaust gas by combusting the raw fuel; and an outer casing, disposed around the reforming reaction tube, having a larger diameter than that of the reforming reaction tube.    USE - The reforming apparatus is useful in a fuel cell for reforming a raw fuel into a hydrogen-rich reformed gas (claimed).    ADVANTAGE - In the reforming apparatus: the reformer, the shift reactor and the selective oxidation unit are housed in the single reforming reaction tube, hence the carbon monoxide contained in the reformed gas can be reduced without the formation of an intricately-shaped passage; the combustion exhaust gas passes through the heated flow passage and the heat required for the reforming reaction within the reforming reaction tube can be supplied, and thus eliminates the requirement of a heating means; and space between the reforming reaction tube and the outer casing serves as the heated flow passage, as a result a passage requiring folded-back portions or many tubes is eliminated, hence the reforming apparatus has simplified structure, exhibits improved thermal efficiency and reforming efficiency, and can be manufactured easily.    DETAILED DESCRIPTION - Reforming apparatus (10) comprises: a reformer (12) which generates a reformed gas from a raw fuel; a shift reactor (14) which reduces carbon monoxide contained in the reformed gas through a shift reaction; a selective oxidation unit (16) which reduces the carbon monoxide contained in the reformed gas that has passed through the shift reactor by performing selective oxidation on the carbon monoxide; a reforming reaction tube (18) which houses linearly the reformer, the shift reactor and the selective oxidation unit; a combustion means which produces combustion exhaust gas by combusting the raw fuel; and an outer casing, disposed around the reforming reaction tube, having a larger diameter than that of the reforming reaction tube, where the reforming reaction tube is arranged vertically so that a reformer side is arranged at a lower position and a selective oxidation unit side is arranged at an upper position, and at least one of the shift reactor and the selective oxidation unit includes a divider member which divides the interior of the reforming reaction tube into an upper portion and a lower portion, and a catalyst supported by the divider member from below.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of the reforming apparatus.    Reforming apparatus (10)    Reformer (12)    Shift reactor (14)    Selective oxidation unit (16)    Reforming reaction tube (18)