NOVELTY - The fuel cell electric power generating system has unit (2a) for generating reformed gas containing hydrogen, fuel cell (1), heat recovery device (3) having heat exchanger (12), supply unit, and pipeline (42). Device (3) burns and carries out heat recovery of anode waste gas of fuel cell. Heat exchanger has a to-be-heated fluid flow path filled with a modification catalyst. Supply unit supplies hydrocarbon group fuel, water or water vapor to flow path. Pipeline supplies fluid passed through the flow path to unit (2a).    USE - For generating electric power.    ADVANTAGE - The system has improved electric power generation efficiency. The reformed-gas generating unit efficiently generates reformed gas containing hydrogen. The heat dissipation amount of heat recovery device is reduced.    DETAILED DESCRIPTION - The fuel cell electric power generating system has a reformed-gas generation unit (2a), a fuel cell (1), a heat recovery device (3) having a heat exchanger (12), a supply unit, and pipeline (42). The reformed-gas generating unit generates reformed gas containing hydrogen by modification reaction using modification catalyst (6). The modification catalyst (6) is formed using hydrocarbon gas fuel, oxygen or air, and water or water vapor as a raw material. The fuel cell generates electric power using the produced reformed gas as a fuel. The heat recovery device burns and carries out heat recovery of anode waste gas of fuel cell. The heat exchanger has a to-be-heated fluid flow path filled with a modification catalyst. The supply unit supplies hydrocarbon group fuel, water or water vapor to flow path. The pipeline supplies fluid passed through the flow path to reformed-gas generation unit. An INDEPENDENT CLAIM is included for operating method of fuel cell electric power generation system.    DESCRIPTION OF DRAWING(S) - The figure shows the systematic view of structure of fuel cell electric power generation system. (Drawing includes non-English language text)    Fuel cell (1)    Reformed-gas generation unit (2a)    Heat recovery device (3)    Modification catalyst (6)    Heat exchanger (12)    Pipeline (42)