NOVELTY - A fuel cell apparatus has fuel cell which produces electric power from fuel gas and oxidizing agent gas, fuel gas flow channel where fuel gas flows toward the upper part from the lower part of the fuel cell, oxidizing agent gas flow path where oxidizing agent gas flows toward the upper part from the lower part of the fuel cell, combustion part where fuel gas and oxidizing agent gas are mixed and burned, and modifier (20) having modification flow path (32) filled with catalyst (39) which modifies fuel gas with heat provided from combustion part to obtain modified gas.    USE - A fuel cell apparatus (claimed).    ADVANTAGE - Downstream catalyst is effectively utilized.    DETAILED DESCRIPTION - A fuel cell apparatus has fuel cell which produces electric power from fuel gas and oxidizing agent gas, fuel gas flow channel formed inside the fuel cell, where fuel gas flows toward the upper part from the lower part of the fuel cell, oxidizing agent gas flow path formed in the exterior of the fuel cell, where oxidizing agent gas flows toward the upper part from the lower part of the fuel cell, combustion part positioned above the fuel cell where fuel gas and oxidizing agent gas are mixed and burned, and modifier (20) having modification flow path (32) filled with catalyst (39) which modifies fuel gas with heat provided from combustion part to obtain modified gas. The modification flow path has upstream flow path (35) which extends without contacting the side wall of the modifier from the upper end of the modification flow path, and a pair of downstream flow paths (36) which branches from the downstream end of the upstream flow path, and winds and extends to the downstream end of the modification flow path. Downstream flow path has 1st meandering flow path (37) extended without contacting the side wall of the modifier from the downstream end of the upstream flow path, and 2nd meandering flow path (38) positioned outside 1st meandering flow path, which contacts the side wall of the modifier and is extended from the downstream end of 1st meandering flow path to the downstream end of the modification flow path.    DESCRIPTION OF DRAWING(S) - The drawing shows a top cross-sectional view of the internal structure of modifier.    Modifier (20)    Modification flow path (32)    Upstream flow path (35)    Downstream flow paths (36)    1st meandering flow path (37)    2nd meandering flow path (38)    Catalyst (39)