FUEL CELL SYSTEM

Provided is a fuel cell system including a fuel cell module including a first fuel cell and a second fuel cell, and an oxidant gas temperature adjustment device for adjusting a temperature of an oxidant gas supplied to the fuel cell module, the first fuel cell being at least configured to reform a fuel gas, wherein the fuel cell system includes a temperature control means for setting a target temperature of the oxidant gas supplied to the fuel cell module such that a temperature of the first fuel cell and a temperature of the second fuel cell do not exceed a prescribed upper-limit temperature and controlling the oxidant gas temperature adjustment device based on the target temperature, and the temperature control means calculates the target temperature T as T=Tmax-ΔT1-ΔT2 (ΔT1>0), T=Tmax-ΔT2 (ΔT1≤0), or T=Tmax (ΔT2