A fuel cell stack includes a first separator and a second separator. A reactant air flow channel is formed on one surface of the second separator. A fuel gas flow channel is formed on one surface of the first separator. Further, a coolant air flow channel is formed on the first separator, on the other surface opposite to the fuel gas flow channel. The reactant air flow channel is connected between a reactant air inlet and a reactant air outlet. A coolant air flow channel is connected between a coolant air inlet and a coolant air outlet. The reactant air flow channel and the coolant air flow channel are configured such that the pressure loss of the reactant air between the reactant air inlet and the reactant air outlet and the pressure loss of the coolant air between the coolant air inlet and the coolant air outlet are substantially the same.