NOVELTY - Fuel cell power generating device has water evaporator (61) generating water vapor which is supplied to modifier (2). The superheater (62) superheats the water vapor. The fuel mixed gas pre-heater (63) heats the hydrogen supplied to the modifier in which hydrogen is mixed with water vapor. The combustion flow path is formed, such that the combustion gas from exhaust gas burner (4) orderly passes through superheater, pre-heater, evaporator and water condenser (5).    USE - Solid high molecular form fuel cell power generating device.    ADVANTAGE - Power generating efficiency is improved. Starting operation is performed in a short duration from stopping state. Exhaust heat is recovered effectively.    DETAILED DESCRIPTION - The circulating pump (132) circulates the cooling medium in the fuel cell which has hydrogen. The fuel cell cooling medium path (131) circulates the cooling medium through the fuel cell and the fuel process cooling medium circulation path (133) branches the cooling medium from the upstream of fuel cell cooling paths and flow together in the downstream of fuel cell. The modifier modifies the mixed air of gas with cooler (134) which removes the calorie from the cooling medium and adjusts the temperature of cooling medium. The water vapor superheater and mixed gas pre-heater are integrated with exhaust gas burner. The water evaporator is integrated to the modifier which is integrated with hydrogen rich gas cooler (22). A desulfurizer (33) provided between hydrogen rich gas cooler and low temperature carbon monoxide conversion device (31), is integrated with conversion device. The starting burner reacts the fuel and oxygen for generating the combustion gas. A junction is formed in the place where the combustion gas is divided between fuel mixed gas pre-heater and water evaporator. The combustion gas is generated during starting and after passing through modification catalyst layer (21), combustion gas flows through desulfurizer, carbon monoxide conversion device and selective oxidation type carbon monoxide removal device (32). Stop valves are provided on both sides of junctions between the starting burner and fuel cell cooling medium heater.    An INDEPENDENT CLAIM is also included for the fuel cell power generating device operation. The temperature of the fuel cell cooling medium heater, desulfurizer, low temperature carbon monoxide conversion catalyst layer, selective oxidation type carbon monoxide removal catalyst layer heated individually by heaters are more than predetermined target temperature or any one reaches the predetermined values during starting time of apparatus. Temperature of water evaporator is made to reach the predetermined value by selectively opening and closing the stop valves.    DESCRIPTION OF DRAWING(S) - The figure shows the block diagram of fuel cell power generating device. (Drawing includes non-English language text).    Modifier (2)    Exhaust gas burner (4)    Water condenser (5)    Modification catalyst layer (21)    Hydrogen rich gas cooler (22)    Low temperature carbon monoxide conversion device (31)    Selective oxidation type carbon monoxide removal device (32)    Desulfurizer (33)    Water evaporator (61)    Superheater (62)    Fuel mixed gas pre-heater (63)    Fuel cell cooling medium path (131)    Circulating pump (132)    Fuel process cooling medium circulation path (133)    Cooler (134)