A fuel cell system for a ship is provided. According to an embodiment of the present invention, the fuel cell system for a ship comprises a plurality of fuel cell stacks mounted on a ship; a fuel amount control valve connected to the fuel cell stacks to control the amount of fuel; a power control part which controls the power of the ship and controls power for the inside of the ship by determining the power demand of loads applied to the ship; a power conversion part for controlling the fuel amount control valve according to power control signals transmitted from the power control part; a plurality of exhaust gas lines connected to the fuel cell stacks; and a manifold connected to the exhaust gas lines to collect exhaust gas discharged from the fuel cell stacks. [Reference numerals] (120) Desulfurizer; (130) Reformer; (140) Pressure tank; (150) Multi-stack room; (160) Power conversion part; (163) Controller; (170) Ship power control part; (180) Ship load; (246) Manifold; (247) Waste heat boiler; (AA) Reforming gas; (BB) Power system
