To improve assembly precision of a fuel cell by improving a sealing property. A first gasket 12 is integrally formed with a first gas diffusion layer 11 and a second gasket 14 is integrally formed with a second gas diffusion layer 13, and a hinge portion 15 connects the first gasket 12 to the second gasket 14. The gas diffusion layer incorporated gasket sandwiches a membrane-electrode from both sides in the thickness direction. A seal protrusion 12c is formed in a surface of the first gasket 12 or the second gasket 14 and comes into close contact with the membrane-electrode.