PURPOSE: To facilitate the position fixation in the installation execution onto a wall surface and improve precision.

CONSTITUTION: As for a composite panel 1 which is formed by attaching a substrate member 3 on the reverse surface of a decoration member 2 by an adhesive, slits 4 and 5 for insertion-engaging a slip-off preventing hardware are formed on the left and right edge surfaces of the decoration member 2, and the decoration member 2 and the substrate member 3 are nipping-held by the slip-off preventing hardware 9 and 11B having the engagement pieces 5 and 12 fitted with the slits 4 and 5 and the nipping pieces 7 and 13 in contact with the reverse surface of the substrate 13. A fixed part 15 for a panel supporting member is extension-installed on the nipping piece 13 on the upper part slip-off preventing hardware 11B, and a tapped hole 8 is formed on the holding piece 7 on other hardware 9, and screw-fixation 10 on the substrate member 3 is performed.