The present invention provides a fuel cell separator having an airtight gasket, in which a gasket is integrally injection-molded in a region that requires airtightness of a fuel cell separator to maintain airtightness of each flow field of the separator and to smoothly guide the fluid flow in each flow field.For this purpose, the present invention provides a fuel cell separator having an airtight gasket, which is integrally injection-molded on both surfaces of the separator to form a closed curve.