A fuel cell system includes an inlet pipe configured to guide a fuel gas injected from an injector to a fuel cell stack, and a gas liquid separator configured to perform gas liquid separation of a fuel exhaust gas discharged from the fuel cell stack. The gas liquid separator is directly coupled to a lower portion of the inlet pipe. A connection channel configured to connect the inside of the gas liquid separator and a channel in the inlet pipe together is formed in a part coupling the gas liquid separator and the inlet pipe together.