PURPOSE: To dispense with driving nails into a modesty panel by allowing a lower rear part which hangs to the rear side of the lower end of a decoration accessory to be engaged with a notched part of an underlayer exterior finish material by way of a water drip piece of a water drip joiner.

CONSTITUTION: An underlayer exterior finish material 3 provided with a notched part 32 behind an upper end 31 is fixed with the surface of a wall underlayer material C where a front part 21, which hangs at the front of a lower end, is provided on the upper part of the underlayer exterior finish material 3, thereby fixing an upperlayer exterior finish material 2 whose thickness is smaller than the underlayer exterior finish material 3. There is formed a lower rear part 16, which hangs behind the lower end of an accessory main body 13 of a decorative accessory 1 which is lone sideways in the horizontal direction and fixed between the underlayer exterior finish material 3 and the upperlayer exterior finish material 2. The rear part 16 is engaged with the underlayer exterior finish material 3 by way of a water drip piece 41 of a water drip joiner 4. An upper rear part 11, which stands behind the upper end face of a decorative accessory 1, is engaged with the front part 21 of the upperlayer exterior finish material 2 by way of a water drip piece 51 of a water drip joiner 5. The top and the bottom of the decorative accessory are engaged respectively with the underlayer exterior finish material and the upperlayer exterior finish material, which makes it possible to fix the wall surface without driving nails.