FUEL CELL SYSTEM

A fuel cell system includes a controller that controls actions of the fuel cell system. The controller includes a freezing presence-absence determination unit that performs freezing presence-absence determination, a temperature raising execution unit that performs temperature raising processing for raising a temperature of an exhaust and drain valve, and a thawing presence-absence determination unit. In the freezing presence-absence determination, freezing determination is made when the exhaust flow rate of gas is equal to or lower than a first threshold. In the thawing presence-absence determination, thawing determination indicating that the exhaust and drain valve is thawed is made when the exhaust flow rate of gas is higher than a second threshold. The second threshold shows a flow rate higher than the first threshold.