To provide a method and a plant for manufacturing a separator for a polymer electrolyte fuel cell for accurately forming a workpiece made of a metal sheet, without deteriorating production efficiency, and of efficiently manufacturing a high-precision separator.

The workpiece 1A, which is wound back from a workpiece coil 1B by a workpiece rewinder 40, includes its inclination angle adjusted by an approach angle adjuster 50 and is guided to a separator forming mill 60 as meandering control is performed. The workpiece 1A is introduced between rolls of the separator forming mill 60 and pressurized to continuously shape a separator 1. Tension control is performed as both width ends of the separator 1 shaped by the separator forming mill 60 are held by a pinch roll device 70 and discharged. The separator 1 discharged by the pinch roll device 70 is cut, without being stopped, by a flying shear 80 at a portion where no flow passage is formed.