NOVELTY - The method comprises forming an outer divided body and an inner divided body, fitting an inner temporary assembly into a frame of an outer temporary assembly to produce a cell assembly temporary assembly, arranging a cell assembly stack in a forming die as a member arrangement step, where the cell assembly temporary assemblies are stacked in the cell assembly stack, and pressurizing and heating the forming die to crosslink the uncrosslinked item for forming a seal member by integrating the outer and the inner divided bodies with each other. Each cell assembly includes an electrode member.    USE - The method of manufacturing a fuel cell module, which is useful as a unit of power generation for automobiles.    ADVANTAGE - The method ensures easy positioning of the structural elements and suppresses the misalignment of the structural elements thus efficiently manufacturing the fuel cell module having a sealed region with high durability and reliability in less consumption of time and without the special treatment for regulating the amount of liquid rubber for impregnation.    DETAILED DESCRIPTION - The method comprises forming an outer divided body and an inner divided body, fitting an inner temporary assembly into a frame of an outer temporary assembly to produce a cell assembly temporary assembly, arranging a cell assembly stack in a forming die as a member arrangement step, where the cell assembly temporary assemblies are stacked in the cell assembly stack, and pressurizing and heating the forming die to crosslink the uncrosslinked item for forming a seal member by integrating the outer and the inner divided bodies with each other. Each cell assembly includes: an electrode member having a membrane electrode assembly formed from an electrolyte membrane, a pair of electrode catalyst layers disposed on both sides of the electrolyte membrane in a thickness direction and a pair of porous layers disposed on both sides of the membrane electrode assembly in the thickness direction; a separator (4) having an electrode member (3) arrangement portion arranged to be stacked with the electrode member, where one side of the electrode member in the thickness direction is in contact with the arrangement portion; a seal member (5) arrangement portion having a frame shape and disposed on an outer side of the electrode member arrangement portion in a planar direction; and a seal member formed from a crosslinked item of solid rubber and disposed in the seal member arrangement portion to seal a peripheral edge portion of the electrode member along a shape of the peripheral edge portion and to integrate the electrode member and the separator with each other. The outer divided body has a frame shape, and is formed from an uncrosslinked item of solid rubber having adhesiveness in the seal member arrangement portion of the separator to produce outer temporary assembly. The inner divided body has a frame shape, and is formed from an uncrosslinked item of solid rubber in the peripheral edge portion of the electrode member to produce inner temporary assembly. The seal member: seals the peripheral edge portion of the electrode member; integrates the electrode member and the separator with each other to produce the cell assembly from the cell assembly temporary assemblies; and integrates the cell assembly temporary assemblies, which are adjacent in the stacking direction, with each other to produce the fuel cell module from the cell assembly stack. The electrode member has a stepped portion that is stepped as viewed in cross section in the thickness direction in a part of the peripheral edge portion, and a die-symmetric stepped portion having a shape that matches the stepped portion is formed on an inner side of the frame of the seal member preform in the preliminary production step. The cell assembly temporary assemblies have a penetration hole through which oxidizing gas, fuel gas and coolant flows, where the hole penetrates in the thickness direction of the electrode member. A plug is disposed in the penetration hole in the member arrangement step such that the uncrosslinked item does not flow into the penetration hole in the integration step, and the plug is removed after the fuel cell module is produced in the integration step. The pair of porous layers is disposed on both sides of the membrane electrode assembly in the thickness direction. The porous layer disposed on one side of the membrane electrode assembly in the thickness direction has a gas diffusion layer, and a gas flow path layer whose porosity or average pore diameter is larger than that of the gas diffusion layer. An area of the membrane electrode assembly is larger than an area of the gas diffusion layer. The uncrosslinked item of solid rubber includes rubber component; a crosslinking agent selected from organic peroxides of which a 1-hour half-life period temperature is less than or equal to 130 degrees C; a crosslinking auxiliary agent; and an adhesive component formed of a resorcinol compound together with a melamine compound and a silane coupling agent. An INDEPENDENT CLAIM is included for a method of manufacturing a fuel cell.    DESCRIPTION OF DRAWING(S) - The diagram shows a perspective view of a module.    Electrode member (3)    Separator (4)    Seal member (5)    Through holes (50a)    Convex portion. (53)