NOVELTY - An oxidation self-heat type reformer (100) comprises modified layer (113) which produces reformed gas which has hydrogen as main component by reforming reaction of mixture of raw material and water vapor of hydrocarbon or aliphatic alcohol, reaction tube (110) which has oxidation heat layer which oxidizes part of raw material or reformed gas and generates heat, mixture supply flow path (122) which supplies mixture in inner tube of reaction tube, and reformed-gas discharge flow path (121) which discharges reformed gas from gap part.    USE - An oxidation self-heat type reformer used for fuel cell system (claimed).    ADVANTAGE - The reformer is inexpensive, and has simple structure and improved reformation efficiency.    DETAILED DESCRIPTION - An oxidation self-heat type reformer (100) comprises modified layer (113) which produces reformed gas which has hydrogen as main component by reforming reaction of mixture of raw material and water vapor of hydrocarbon or aliphatic alcohol, reaction tube (110) which has oxidation heat layer which oxidizes part of raw material or reformed gas and generates heat, oxidizing-gas supply unit which supplies oxidizing gas to oxidation heat layer, heating unit which makes high temperature combustion gas contact outer periphery of reaction tube and heats inside of reaction tube, mixture supply flow path (122) which supplies mixture in inner tube of reaction tube, and reformed-gas discharge flow path (121) which discharges reformed gas from gap part. The reaction tube has double-pipe structure in which end is closed and inner tube and outer tube are connected in closed edge part. The oxidation heat layer which is located in gap part of outer tube and inner tube, and modified layer which is located in inner tube. An INDEPENDENT CLAIM is included for a fuel cell system.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of oxidation self-heat type reformer. (Drawing includes non-English language text).    Oxidation self-heat type reformer (100)    Reaction tube (110)    Modified layer (113)    Reformed-gas discharge flow path (121)    Mixture supply flow path (122)