PURPOSE: To obtain a molten carbonate fuel cell stack having corrosion resistant gas sealing structure by forming a specific corrosion resistant layer at each edge of a conductive separator having a fuel gas supply passage and an oxidizing agent gas supply passage on its both sides.

CONSTITUTION: Before side wall members 6a, 6b of a separator 4a are mounted to a separator plate 5, a 100μm thick aluminium foil is clad in each A portion of the members 6a, 6b, and an alumite layer is formed on the clad surface with all surfaces other than the clad surface masked. The alumite surface is coated with lithium-potassium carbonate and they are heated. Thereby, a corrosion resistant layer 10 comprising pillar-shaped holes 11, a lithium aluminate porous layer, a lithium aluminate barrier layer, and an aluminium base layer is obtained. The separator plate 5 having this separator 4a is combined with an electrolyte plate, an oxidizing agent electrode, and a fuel electrode, and they are stacked, and manifolds are mounted to the stack to obtain a fuel cell.