NOVELTY - A fuel cell electric power generation system comprises desulfurizer (4) which reduces content of sulfur compound contained in liquid fuel supplied from primary liquid fuel tank, reformation fuel gas-liquid separator which extracts gas from liquid fuel, reformer (3) which produces reformed gas containing hydrogen from liquid fuel stored in secondary liquid fuel tank, and liquid level control part which controls liquid level of bypass fuel gas-liquid separator so that liquid level becomes lower than connection part of bypass fuel gas-liquid separator and overflow piping.    USE - Fuel cell electric power generation system.    ADVANTAGE - The fuel cell electric power generation system suppresses mixing of combustible gas with liquid fuel.    DETAILED DESCRIPTION - A fuel cell electric power generation system comprises primary liquid fuel tank which stores liquid fuel, desulfurizer (4) which reduces content of sulfur compound contained in liquid fuel supplied from primary liquid fuel tank, reformation fuel gas-liquid separator arranged downstream from desulfurizer which extracts gas from liquid fuel, secondary liquid fuel tank installed in upstream of desulfurizer which stores remaining liquid fuel that extracted gas by reformation fuel gas-liquid separator, reformer (3) which produces reformed gas containing hydrogen from liquid fuel stored in secondary liquid fuel tank, fuel cell main body (2) which is generated using reformed gas supplied from reformer, burner combustion part which takes in waste gas discharged from fuel cell main body, burns and heats reformer, bypass fuel gas-liquid separator which returns remaining liquid fuel that extracted gas to primary liquid fuel tank, edge part which is connected to reformation fuel gas-liquid separator, other edge part which is connected to bypass fuel gas-liquid separator, overflow piping in which part of liquid fuel in reformation fuel gas-liquid separator is distributed toward bypass fuel gas-liquid separator, and liquid level control part which controls liquid level of bypass fuel gas-liquid separator so that liquid level becomes lower than connection part of bypass fuel gas-liquid separator and overflow piping. An INDEPENDENT CLAIM is included for a method of operating fuel cell electric power generation system.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of the fuel cell electric power generation system. (Drawing includes non-English language text).    Fuel cell package (1)    Fuel cell main body (2)    Reformer (3)    Desulfurizer (4)    Liquid fuel tank (5)