PURPOSE: To improve the working efficiency when a laminate layer cell is assembled by providing at least a process to engrave slits to a separator, a process to position and connect closely the separator, an electrode plate, and an end block, in a metal mould, and a process to inject a molten resin into the metal mould.

CONSTITUTION: At a separator 18, slits 28 are engraved between its cell reaction part 24 and channels 22-1 and 22-2 formed at both surfaces of the front and the rear sides, and slits 128 of an electrode 10 and slits 228 of and end block 26 are engraved in a slender form at the positions responding to the slits 28. These slits are penetrated by pins 34 which project at the inside of a left metal mould 30 of the left and right metal moulds which can be cut into two pieces, and positioned automatically, holding all the members on condition of floating from the bottom surface of the metal mould. Then, by closing the both metal moulds while compressing by pressure projections 36 furnished at the inner walls of the metal moulds, and pulling out the pins 34, the laminate layer cell 38 is set on condition of floating in the metal moulds. Finally, by injecting a molten resin from an injection port 40, the molten resin is poured to the periphery of the laminate layer cell 38 and the slits 28, 128 and 228.