To provide a sealing structure, for an ozone catalytic pond, which is capable of positively preventing an exhaust ozone from spreading.

An exhaust ozone decomposition material 8 composed of a particulate active carbon packed in an annular bag is arranged wrapping the peripheral edge part 6a of a lid form 6 and an abutting seam 6b from which the exhaust ozone leaks. It is possible to completely wrap both peripheral edge part 6a of the lid form 6 and abutting seam 6b as the exhaust ozone decomposition material 8 is changeable in shape. Consequently, the leaking exhaust ozone is totally caused to pass through the interior of the exhaust ozone decomposition material 8 and therefore, is converted to a harmless carbon dioxide and oxygen through a chemical reaction with the particulate active carbon.