NOVELTY - In the fuel cell stack, the gaseous fuel, oxidant gas and cooling water flow into the cell laminate from one end of the cell laminate in the laminate direction. Exhausts of the gaseous fuel, oxidant gas and cooling water flow out of the cell laminate in the opposite direction.    USE - The fuel cell stack is used for portable power sources, electric vehicle power sources and domestic cogeneration systems.    ADVANTAGE - The fuel cell stack is small and lightweight and has a high degree of freedom when the stack is mounted on a variety of equipment.    DETAILED DESCRIPTION - A polymer electrolyte fuel cell stack includes a cell laminate (1), which has a number of unit cells that are laid one upon another via conductive separators. Each unit cell includes a polymer electrolyte membrane, a pair of electrodes arranged across the membrane and respectively have a catalytic reaction layer, and a unit for feeding gaseous fuel containing hydrogen to one electrode and oxidant gas containing oxygen to the other electrode. An inlet manifold (2) distributes gaseous fuel, oxidant gas and cooling water in a sequence of lamination from a unit cell on the first end of the cell laminate to a unit cell on the second end of the cell laminate. An outlet manifold (3) discharges exhausts of the gaseous fuel, oxidant gas and cooling water in an inverted sequence of lamination from the unit cell on the second end of the cell laminate to the unit cell on the first end of the cell laminate.    INDEPENDENT CLAIMS are also included for the following:    (a) a polymer electrolyte fuel cell that includes a number of cell laminates and a number of end plates that are arranged, so that each cell laminate is interposed between a pair of end plates. Flow paths of gaseous fuel, oxidant gas and cooling water formed in the end plates are respectively connected or linked via a fluid sealing mechanism; and    (b) a method of installing a polymer electrolyte fuel cell stack.    DESCRIPTION OF DRAWING(S) - The diagram illustrates a fuel cell stack.    Cell laminate (1)    Inlet manifold (2)    Outlet manifold (3)    Collecting members (8)    Fastening belt (9b)