PURPOSE: To adsorb a seal securely and entirely with a uniform force by disposing an air-impermeable elastic body such as rubber around the outer peripheral of a base, disposing an continuously foaming and elastic foam body such as sponge around the inner peripheral of the air-impermeable elastic body, and sucking the air from the foam body portion.

CONSTITUTION: A ring-like rubber member 7, which is an air-impermeable elastic body, is disposed around an upper outer periphery of a base, and a sponge 8, which is a continuously foaming and elastic foam body, is disposed on the inner side of the rubber member T. Air suction holes 6a are formed in the underside of the sponge 8. A seal S is placed on the upside of the ring member 7 and the sponge 8 so as to be adsorbed by sucking the air from the suction holes 6a through the sponge 8. At this time, the air is prevented from leaking from the gap between the outer peripheral portion 7 and the seal S, thus realizing uniform and secure suction by a strong suction force even in the case of a soft seal since the adsorption is performed with the whole sponge 8.