PURPOSE: To obtain excellent durability by integrally installing a sealing material for a rain barrier and a sealing material for a wind barrier onto a wall panel and filling the insides of the sealing materials with a fire-resisting insulating material.

CONSTITUTION: Recesses 6 are formed to the end faces of adjacent wall panels 1 in the vertical direction, and rails 7 are buried into the recesses 6 and fixed onto anchors 8. Sealing grooves 10 and rain-barrier mounting grooves 11 are formed to the external side faces of the rails 7, and sealing materials 2 for a wind barrier are fitted into the sealing grooves 10. Sealing materials 17 for a rain barrier are set up outside the sealing materials 2, and the insides of the sealing materials 2 are filled with a fire-resisting insulating material 18 and an airtight sealing material 19. Accordingly, waterproofness, airtightness, heat-insulating properties, etc., can be improved.