Abstract: In a sealing device (1) installed in an installation groove (4) provided in one member (2) of two members (2, 3) facing to each other so as to be brought into close contact with the other (3), the sealing device has a seal ring (11) and a backup ring (21) arranged in a low-pressure side (L) of the seal ring (11), the installation groove (4) has a slope bottom surface (4c), the backup ring (21) has a slope surface (21a). The sealing device (1) is to be made such that the seal ring (11) made of a rubber-like elastic body is prevented from being damaged by the backup ring (21) made of a hard material. In order to achieve this object, a second backup ring (31) is arranged between the seal ring (11) and the backup ring (21), and formed by a softer material than the backup ring (21).

Abstract: In a sealing device (1) installed in an installation groove (4) provided in one member (2) of two members (2, 3) facing to each other so as to be brought into close contact with the other (3), the sealing device has a seal ring (11) and a backup ring (21) arranged in a low-pressure side (L) of the seal ring (11), the installation groove (4) has a slope bottom surface (4c), the backup ring (21) has a slope surface (21a). The sealing device (1) is to be made such that the seal ring (11) made of a rubber-like elastic body is prevented from being damaged by the backup ring (21) made of a hard material. In order to achieve this object, a second backup ring (31) is arranged between the seal ring (11) and the backup ring (21), and formed by a softer material than the backup ring (21).