A fuel cell is provided with a membrane electrode assembly provided with a frame, both of which are sandwiched between two separators. The fuel cell is configured such that reactive gas is circulated between the frame and the separators. The frame and both separators each have manifold holes, the rims of the manifold holes of frame extend into the manifold holes in the separators, and protrusions cover the inner peripheral surfaces of the manifold holes in at least one of the separators. This structure makes possible the easy and accurate position and integration of the separators and the frame, and fuel cell miniaturization can be achieved because space to position the protrusions is not needed.