NOVELTY - The apparatus has fuel channel that is formed in cylindrical container (1). A heater (3) is positioned along fuel flow direction. The position of dehydrogenation reaction is changed by using heater to change temperature distribution in desulfurization agent layer (2) in fuel flow direction. A desulfurization catalyst generates hydrogen by dehydrogenation of fuels, and hydrodesulfurizes using the hydrogen according to usage log. The dehydrogenation reaction is changed in direction of fuel flow so that temperature of dehydrogenation is maintained at lower temperature.    USE - Temperature control apparatus of desulfurizer for desulfurization of liquid fuel such as kerosene and gaseous fuel, used for hydrogen production apparatus in fuel cell system. Can also be used in town gas and liquefied petroleum gas.    ADVANTAGE - Since the desulfurization catalyst is used as desulfurization agent for producing hydrogen from the portion of fuel through a dehydrogenation reaction and hydrodesulfurization is performed using the hydrogen, the desulfurization agent in the entire region of a desulfurization agent layer in the direction of fuel flow is effectively used and the service life of desulfurizer is increased.    DETAILED DESCRIPTION - The temperature gradient with increase of a usage log is maintained and temperature is raised, if the fuel flow in the upper stream is in lower temperature. The heater control unit raises the upstream temperature so that temperature gradient is eliminated when the temperature gradient of fuel flow in up-stream direction is lower. The heater control unit controls the dehydrogenation temperature in high temperature if the dehydrogenation reaction temperature in down-stream is lower. The control unit controls the temperature of dehydrogenation temperature same as that of dehydrogenation reaction temperature. The control unit controls the dehydrogenation temperature lower than the dehydrogenation reaction temperature. The heater varies the heat generation ratio of the fuel flow direction in the desulfurizing agent layer so that the energizing amount to the heater is increased with increase of usage log. The heater element is arranged in the fuel flow direction in the desulfurizing agent layer. The heater control part controls the energizing amount of heater elements separately, and changes temperature distribution. The accumulation fuel supply amount or accumulation fuel-supply time to the desulfurizer is used as usage log. An INDEPENDENT CLAIM is included for temperature control method of desulfurizer.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of the desulfurizer.    Cylindrical container (1)    Desulfurization agent layer (2)    Heater (3)    Upper space (5)    Fuel inlet tube (6)