NOVELTY - A fuel cell power generation system (1) comprises modifier (11) which produces hydrogen rich reformed gas from raw fuel gas, carbon monoxide conversion device (12) to which concentration of carbon monoxide in reformed gas obtained by modifier is reduced, fuel cell (21) which generates electrical energy according to electrochemical reaction of fuel gas and oxidizing agent gas, carbon monoxide conversion device heater (12b) which increases temperature of carbon monoxide conversion device, and control apparatus which controls preset temperature of carbon monoxide conversion device heater.    USE - A fuel cell power generation system (claimed).    ADVANTAGE - Reliability and energy saving performance of the fuel cell power generation system are improved.    DETAILED DESCRIPTION - A fuel cell power generation system (1) comprises modifier (11) which produces hydrogen rich reformed gas from raw fuel gas, carbon monoxide conversion device (12) to which concentration of carbon monoxide in reformed gas obtained by modifier is reduced, fuel cell (21) which generates electrical energy according to electrochemical reaction of fuel gas and oxidizing agent gas, carbon monoxide conversion device heater (12b) which increases temperature of carbon monoxide conversion device, and control apparatus which controls preset temperature of carbon monoxide conversion device heater. Control apparatus has unit to compute preset temperature of carbon monoxide conversion device heater according to accumulation of fuel cell, unit to compute heater injection quantity, and unit to control carbon monoxide conversion device heater based on computed heater injection quantity. An INDEPENDENT CLAIM is included for control method of carbon monoxide conversion device heater.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of the fuel cell power generation system. (Drawing includes non-English language text).    Fuel cell power generation system (1)    Modifier (11)    Carbon monoxide conversion device (12)    Heater (12b)    Fuel cell (21)