A solid oxide fuel cell system has a carbon monoxide generator using ash-free coal or graphite, which includes a carbon supply unit, a carbon dioxide supply unit, a carbon monoxide generating unit, and a fuel cell unit. The carbon monoxide generating unit supplies CO to the anode of the fuel cell unit, and CO2 discharged from the fuel cell unit is recycled to the carbon dioxide supply unit. Because ash-free coal or graphite is used, a separate reformer does not need to be used, and thus energy can be produced with high efficiency even at low costs. Because CO2 discharged from the solid oxide fuel cell, which uses carbon monoxide as a fuel, after a fuel cell reaction, is reused as reactant gas, carbon dioxide is not emitted into the atmosphere. Gasification can be smoothly achieved by the carbon monoxide generating unit including heating powder or a heating reaction chamber.