A fuel cell, for example, a polymer electrolyte fuel cell, is generally used in a stacked structure where a plurality of power generation layers, each including an electrolyte membrane and a pair of electrodes (anode and cathode), are stacked via separators for separating a fuel gas and an oxidizing gas used as reactive gases from each other. Flow paths that allow fluids, such as the reactive gases and a cooling medium (e.g., coolant) to flow are formed inside of the fuel cell.
One known structure of the separator for fuel cell is manufactured by processing a plate-like member to have a corrugated cross section where first grooves that are concave to one surface and second grooves that are concave to the other surface are arranged alternately and repeatedly. In the separator of this structure, a flow path for one fluid (for example, coolant) is formed on one surface of the first groove, while a flow path for another fluid (for example, fuel gas) is formed on the other surface of the second groove. Another known structure of the separator for fuel cell has a series of rectangular projections arranged in the form of columns on the surface, where cavities between the projections are used as the flow path that allows a fluid to flow both horizontally and vertically.