A fuel-cell-system providing structure is provided which is capable of preventing a collision of a fuel cell with a related apparatus of the fuel cell while suppressing the increase in weight of a vehicle. A fuel cell system provided in a vehicle includes: a fuel cell unit in which a fuel cell is contained; and a related apparatus that is electrically connected to the fuel cell and that is located adjacent to the fuel cell unit. The related apparatus is arranged at a position closer to an outer surface of the vehicle than the fuel cell unit.