PURPOSE: To save a large quantity of trouble and the time in assembly on a site, and to prevent the leakage of water positively.

CONSTITUTION: In a facing panel, second panels 2 are mounted on both sides of a first panel 1, and third panels 3 are installed on both sides of the second panels 2. In the first panel 1, a plurality of unit panels, to which facing plates 7 are set up, are bonded in the vertical direction. In the second panels 2, two posts 9 are arranged in parallel, end sections in the cross direction of the facing plates 7 are disposed so as to be positioned along both posts 9 and the facing plates 7 are fixed onto the posts 9, the base end sections of T-shaped sectional decorative sheets 14 are fastened onto the posts 9 so as to surround the end sections of the facing plates by T shapes, and sealing materials 32 are inserted to both end sections of the facing plates 7. In the third panels 3, the facing plates 7 are fitted onto channel-shaped frame bodies 15.