SEPARATOR FOR FUEL CELL

A separator for a fuel cell includes a reaction region, a pair of manifold regions on opposite sides of the reaction region and through which a plurality of manifolds pass, configured to introduce or discharge reaction gas or coolant, and a pair of diffusion regions between the reaction region and the manifold regions, configured to diffuse a flow of the reaction gas or coolant. Diffusion ribs in the diffusion regions are spaced apart from each other along the manifolds. The diffusion ribs may be spaced apart such that diffusion flow fields formed between the diffusion ribs have different cross-sectional areas for respective regions at ends adjacent to the manifold regions.