A fuel reforming system and a fuel cell system including the same, the fuel reforming system including: a fuel reformer adapted to produce a reformed gas having hydrogen as a main component from a fuel containing hydrogen; a carbon monoxide (CO) remover adapted to remove carbon monoxide from the reformed gas; a heat source adapted to supply heat energy to the reformer and the CO remover; and a moving unit adapted to move the heat source between the fuel reformer and the CO remover. With this configuration, the fuel reformer and the CO remover can be directly heated by a heat source. Then, when the temperature of the CO remover reaches a catalyst activation temperature, the heat source can be moved to directly heat only the fuel reformer, thereby enhancing a reforming effect and a power generation efficiency of the fuel reforming system.