NOVELTY - The desulfurizer (100) has a vessel having a fuel inlet (5) and a fuel outlet (9). A duct formation structure is arranged within vessel and is provided with a rectangular partition section (2) and a rectangular dispersion section (3). Three sides of partition section are perpendicularly affixed to upper surface (4a), front side surface (4c) and back side surface (4d) of vessel, and remaining side is perpendicularly affixed to dispersion section. The fuel inlet and fuel outlet are positioned towards upper surface of vessel from dispersion section, and are separated by partition section.    USE - Desulfurizer for removing sulfur compound from hydrocarbon fuel such as liquefied natural gas (LPG), kerosene, and alcohol used in hydrogen production apparatus of fuel cell system.    ADVANTAGE - The simple structured desulfurizer is designed easily while improving the desulfurization efficiency and improving fuel dispersion properties. Since distance between desulfurizing agent and flow central line can be made small, the fuel can be distributed to the whole desulfurizing agent in vessel. Hence contacting efficiency with desulfurizing agent can be improved, and desulfurization efficiency can be improved.    DETAILED DESCRIPTION - A pair of parallel sides of dispersion section is not in contact with inner walls of vessel, and another pair of sides are perpendicularly affixed to the inner wall of front side surface and back side surface of vessel, and specific side of partition section. The specific side of partition section is not in contact with vessel. The aperture ratio of the flow-path cross section of dispersion section is 30 to 70%. One of the sides of the partition section is in contact with upper surface of vessel. The fuel inlet or fuel outlet is formed in the upper surface of the vessel.    DESCRIPTION OF DRAWING(S) - The drawing shows the front and side views of the desulfurizer.    Rectangular partition section (2)    Rectangular dispersion section (3)    Upper surface (4a)    Front side surface (4c)    Back side surface (4d)    Fuel inlet (5)    Fuel outlet (9)    Desulfurizer (100)