NOVELTY - Multiple cylindrical shape water vapor modifier comprises cylindrical body, burner (6) positioned at radial direction center part of first cylindrical body, modification-catalyst layer provided in lower gap, flow path of reformed gas, cylindrical partition (70) positioned in upside gap, combustion gas flow path provided in gap between first cylindrical body and cylindrical partition, and pre-heating layer with raw fuel, water and/or water vapor (13) provided in gap between second cylindrical body and cylindrical partition.    USE - Multiple cylindrical shape water vapor modifier used for fuel cells.    ADVANTAGE - The modifier is compactized and cost-reduced.    DETAILED DESCRIPTION - Multiple cylindrical shape water vapor modifier comprises cylindrical body which consists of first cylindrical body (1) with large diameter, second cylindrical body (2) and third cylindrical body (3), burner (6) positioned at radial direction center part of first cylindrical body, modification-catalyst layer provided in lower gap among gaps divided into radial direction by first cylindrical body and second cylindrical body, flow path of reformed gas positioned in gap divided into radial direction by second cylindrical body and third cylindrical body, cylindrical partition (70) positioned in upside gap among gaps divided into radial direction by first cylindrical body and second cylindrical body, combustion gas flow path provided in gap between first cylindrical body and cylindrical partition, and pre-heating layer with raw fuel, water and/or water vapor (13) provided in gap between second cylindrical body and cylindrical partition.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of multiple cylindrical shape water vapor modifier. (Drawing includes non-English language text).    First cylindrical body (1)    Second cylindrical body (2)    Third cylindrical body (3)    Burner (6)    Pre-heating layer with raw fuel, water and/or water vapor (13)    Cylindrical partition (70)