To provide an expanded graphite ring packing preventing the oxidation extinguishing of expanded graphite even in a temperature range exceeding a usage limit, keeping excellent sealing performance, and preventing squeezing out of the expanded graphite due to fastening.

In this expanded graphite ring packing A provided with a metallic grommet B, an surface portion b1 of the metallic grommet B, covering an end surface in an axial direction of the ring packing, is formed to be an arc-shape in a cross section having a radius R of curvature. The surface portion b1 is squashed by fastening force, and the width W of the grommet is widened. So that, the grommet tightly contacts with an inner peripheral surface of a vessel body 1 of a pressure vessel and an outer peripheral surface of a covering body 2, thereby giving good sealing performance between them.