A sealing structure includes a hub, an outer-periphery-side mass body, an outer-periphery-side damper elastic body, an inner-periphery-side mass body, and an inner-periphery-side damper elastic body. The hub is attached to one end of a rotary shaft of an object to be attached. The oil seal includes a seal lip in an annular shape and a side lip in an annular shape and is oriented to the inner-periphery-side mass body, is attached in a through hole in the object to be attached, and hermetically seals a void between the hub and the object to be attached. The inner-periphery-side mass body forms at least a part of a pocket which is composed of a recessed portion in an annular shape, and the side lip forms a labyrinth seal which is composed of a gap in an annular shape between the side lip and the pocket.