Fuel cell stack

A fuel cell stack formed by alternately stacking separators and fuel cell units each comprising a solid polymer ion exchange membrane interposed by an anode electrode and a cathode electrode, said fuel cell stack comprising:

• a cooling medium supply port corresponding to a central portion of an electrode power-generating section and a cooling medium discharge port corresponding to an outer circumferential portion of said electrode power-generating section, provided in a flat surface opposed to said anode electrode or said cathode electrode of at least one of said separators;
• and
• a cooling medium flow passage having a spiral configuration for making communication between said cooling medium supply port and said cooling medium discharge port, formed in said flat surface,
• wherein said cooling medium flows in a direction from said central portion to said outer circumferential portion.