PURPOSE: To prevent blocking-up of gas while reducing liquefaction or droplet formation of vapor of generating water or moving water in a cathod pole by arranging an interval or a cross sectional shape of a cooling water passage so as to be changed toward the downstream area from the upstream area of an oxidating agent passage.

CONSTITUTION: An anode pole 33 and a cathode pole 34 are laminated above and below electrolyter 32, and a liminated body 31 is formed, and a fuel distributing plate 20 having a fuel passage 35 is arranged upstream of this laminated body 31, and an oxidating agent distributing plate 38 having an oxidating agent passage 37 and a cooling water distributing plate 40 having a cooling water passage 39 are arranged respectively downstream of this. Since the interval of the cooling water passage 39 is made large toward a downstream area from the upstream area of the oxidating agent passage 37, battery cooling capacity becomes small toward the downstream area from the upstream area, so that an oxidating agent gas temperature is raised as a position comes to the downstream area from the upstream area of the oxidating agent passage 37. Thereby, a quantity by which generating water and moving water by battery reaction can be taken in an oxidating agent as vapor is increased toward the downstream from the upstream, and gas comes to be diffused and discharged easily, and blocking-up of gas in a porous carbon electrode can be prevented, so that the stable battery reaction can be continued.