Fuel cells stack

A fuel cells stack comprising:

• a plurality of fuel cells each arranging an electrode on both sides of a solid electrolyte,
• separators, each including a gas impermeable and dense plate having a conductivity and gaskets, laminated to form a plurality of layers,
• current collectors gripping both ends of said fuel cells stack,
• a fuel gas flow passage for supplying a fuel gas to the fuel cell provided on one side surface of the fuel cell, and an oxidizing agent gas flow passage for supplying an oxidizing agent gas to the fuel cell provided on the other side surface of the fuel cell, wherein:
• any one of said fuel gas flow passage, said oxidizing agent gas flow passage and a cooling water flow passage used for cooling said fuel cell is provided on a side surface of at least one of said fuel cell and the laminated separator, and the fuel gas flow passage, the oxidizing agent gas flow passage and the cooling water flow passage provided in said separator are constituted by a combination of the gasket formed in a one-piece configuration with the separator and a diffuser formed in a one-piece configuration with the separator and comprising a gas permeable body made of a material having a conductivity, said gasket and said diffuser form a pattern of at least one of said fuel gas flow passage, said oxidizing agent gas flow passage and said cooling water flow passage, and said diffuser seals a gap in at least one of said fuel gas flow passage, said oxidizing agent gas flow passage and said cooling water flow passage.