FUEL CELL SYSTEM

A fuel cell system configured to enhance the life of a fuel cell is provided. The fuel cell system a fuel cell, an oxidant gas supplier configured to supply oxygen-containing oxidant gas to a cathode of the fuel cell, a fuel gas supplier configured to supply hydrogen-containing fuel gas to an anode of the fuel cell, an oxygen partial pressure estimator configured to estimate an oxygen partial pressure of the cathode of the fuel cell, a hydrogen partial pressure estimator configured to estimate a hydrogen partial pressure of the anode of the fuel cell, and a controller, wherein the controller calculates a target hydrogen partial pressure by a given equation (1), and wherein the controller controls the hydrogen partial pressure of the anode to the target hydrogen partial pressure.