Abstract: A method of manufacturing a separator includes subjecting a metal thin sheet material to be transported to stepwise forming working at an identical location by a plurality of press machines having different working shapes and arranged sequentially from an upstream side to a downstream side in a transport direction of the metal thin sheet material to form a flow passage groove. The thin sheet material is subjected to annealing treatment in at least one space of spaces between the press machines arranged adjacent to each other in the transport direction of the thin sheet material.