PURPOSE: To arrange so that fitting may be simple and bonding may be able to be done firmly and water proof treatment may be conducted easily by using a water passing and ventilating quality water proof board whose one side is provided with a water proof layer, and making provision at a body surface so that liquid penetrating the body and leaking on the opposite side may be prevented.

CONSTITUTION: A body 10 which administers water-proof treatment is bonded by the use of a water proof system bonding agent 2' with a water proof board 3 one side of whose board material bonded with spherical granules, is fitted with a water proof layer 2, and with a water proof board 4 whose uneven pillar shape is fitted with a board shaped adiabatic material and which has a water proof layer 2 at the opposite surface, and water proofing is completed. Also, the fitting of water proof boards 3, 4 is done in such a way that a guide 21, a bonding agent 20 and a pressurizing flange 22 are inserted into a separating hole, and a water stopping bolt 18 is screwed in, and a flange 24 contacting a metal washer bolt 19 and a water proofing bonding agent 23 are fixed at the outer perimeter of the separating hole. The hollow portions 5 of water proof boards 3, 4 are formed between the body 10 and the water proof layer 2 at the water proof board surface, and should leakage or the like occur, leaking liquid is led to hollow portions 5.