To provide a clamping ring, press-bonding an air-tight sheet to a wall material to recover the air tightness of a dwelling house.

In this clamping ring, a ring A and a ring B are provided with a slit, and easily inserted in an opened hole. After insertion, the rings A and B are restored to the initial size. The rings A and B are provided with projecting and recessed parts, whereby when the rings are pressed to be contracted to the thickness of a wall material or the like, the rings A and B engage with each other to press-bond the air-tight sheet to the wall material or the like.