FUEL CELL SYSTEM

A fuel cell system to be mounted on a vehicle includes a fuel cell configured to generate electric power through chemical reaction of reactive gases, a gas-liquid separator configured to separate water from an off-gas discharged from the fuel cell and store the separated water, a discharge valve configured to drain the water flowing out through an opening at a bottom of the gas-liquid separator, an attitude control device configured to control an attitude of the gas-liquid separator relative to the vehicle, and an instruction device configured to send an instruction for a control target of the attitude of the gas-liquid separator to the attitude control device.