NOVELTY - A fuel reformer (10) provided with a modification catalyst which reforms a fuel in the mixed gas of a fuel and air, and produces hydrogen, comprises: a fuel-supply path; a fuel-supply-control means; a first air supply path; a first air supply control means; a second air supply path; a second air supply control means; a switch means; a reformation means; and a reproduction means.    USE - The fuel reformer is useful for industrial and commercial applications.    ADVANTAGE - The fuel reformer is highly efficient, and cost effective.    DETAILED DESCRIPTION - A fuel reformer provided with a modification catalyst which reforms a fuel in the mixed gas of a fuel and air, and produces hydrogen, comprises: a fuel-supply path which goes downstream from the upstream of the modification catalyst, and supplies a fuel; a fuel-supply-control means to control feed rate of a fuel via the fuel-supply path; a first air supply path which goes downstream from the upstream of the modification catalyst, and supplies air; a first air supply control means which controls feed rate of air via the first air supply path; a second air supply path which goes upstream from the downstream of the modification catalyst, and supplies air; a second air supply control means which controls feed rate of air via the second air supply path; a switch means to select either execution of the first air supply control by a the first air supply control means or execution of the second air supply control by a the second air supply control means; a reformation means to perform the reformation process which reforms a fuel by selecting execution of the first air supply control by the switch means while performing fuel supply control by the fuel-supply-control means; a reproduction means to perform reproduction processing which burns the coke and unreacted component which were deposited on the modification catalyst by selecting execution of the second air supply control by the switch means, and reproduces the modification catalyst at the specified period after execution of the reformation process.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a fuel reformer.    Fuel reformer (10)    Modifier (13)    ECU/a fuel-supply-control means, a first air supply control means, a second air supply control means, the switch means, the reformation means, the reproduction means, a deposition amount estimation means (19)    Fuel feeding pipe (111)    Fuel cap valve/fuel-supply-control means (112)    First switching valve/switch means (116A)    Second switching valve/switch means (116B)    First air supply pipe (117)    Second air supply pipe (118)    Air valve/a first air supply control means, a second air supply control means (119)    Upstream temperature sensor/upstream catalyst temperature detection means (171)    Downstream temperature sensor/downstream catalyst temperature detection means (172)