To provide a seal ring 1 whose sealing performance degradation is avoided without an increase in facility and cost due to additional machining for adhesion prevention.

The seal ring 1 is formed of an elastic material laid between two members opposed to each other in the axial direction. On both axial side, it has sealing faces 13, 14 to be wholly put in close contact with the two members in a mounted condition. The sealing faces 13, 14 are faces not parallel to a plane perpendicular to an axis O in a load eliminated condition, such as inclined faces symmetrical to each other. The seal rings 1, when laid one on another in the axial direction, have a smaller contact area to prevent their mutual adhesion. In the mounted condition, they are compressed to wholly put the sealing faces 13, 14 in close contact with the two members, securing improved sealing performance.