A fuel cell system configured to supply electric power to load includes: a fuel cell; and a control unit configured to set target electric power to be generated by the fuel cell and control electric power generation by the fuel cell such that the fuel cell generates the target electric power. The control unit is configured to, when setting the target electric power using request electric power that the load requests the fuel cell to generate, execute a fluctuation suppression process for making a fluctuation of the target electric power smaller than a fluctuation of the request electric power.