PURPOSE: To make uniform temperature distribution in a reforming section of an alcohol reforming apparatus and to reduce fuel consumption and to improve stability of the engine by making the length of a reforming catalyst layer short at the inlet side of exhaust of the engine.

CONSTITUTION: Alcohol introduced from an inlet 12 is evaporated in an evaporating section 9 and obtd. vapor is led into an inlet chamber 14a of a reforming apparatus through a passage shown by a chain line. Then, the vapor is led into plural number of reforming section 5 (6 is catalyst) partitioned by fins 28 through small holes 27a on a catalyst supporting member 27 and is reacted therein, and produced H2-rich gas is taken out from an outlet 15 of reformed gas through small holes on the catalyst supporting member 7 and through an outlet chamber 15a. Since the above described reaction is an endothermic reaction, necessary heat is supplied utilizing the heat of exhaust gas of the engine introduced from an inlet 18 and exhausted from an outlet 19. In the above- described apparatus, the length of catalyst layer 25 of parallelly installed each reforming section 5 is arranged in such a manner that the length is shorter, the nearer the layer 25 is to the inlet side 18 of the exhaust gas of the engine.