A fuel cell system for a ship is provided. According to an embodiment of the present invention, the fuel cell system for a ship includes a multi-stack room mounted on a ship to accept a plurality of fuel cell stacks; a fuel supply part room to accept a fuel supply part for supplying a fuel to the fuel cell stacks; a pressure tank room to accept a pressure tank for storing the fuel supplied from the fuel supply part; a power control part room to accept a power control part for controlling power required for the inside of the ship by controlling the power of the ship and determining the power demand of loads applied to the ship; a plurality of fuel amount control valves connected to the fuel cell stacks; and a power conversion part accepted in the power control part room to control the fuel amount control valves according to control signals from the power control part. [Reference numerals] (120) Desulfurizer; (121) Heat exchanger; (130) Reformer; (140) Pressure tank; (160) Power conversion part; (163) Controller; (170) Ship power control part; (180) Ship load; (AA) Reformed gas; (BB) Negative pressure
