To facilitate construction by fastening a plate for stay installation on a reinforcing frame furnished with a handrail wall panel on the side of a surface and fastening a stay to support a handrail on this plate for stay installation.

A steel made grillwork reinforcing frame 12 is compounded on the side of a back surface of a handrail wall panel 1 to be set on a margin of a balcony, and a plate 7 for stay installation is clamped on the reinforcing frame 12. Thereafter, a stay 9 is formed of a base part 91, two pieces of left and right longitudinal rods 92 extending upward from the base part 91 and a rail receiver part 93, and this stay 9 is installed on the plate 7 for stay installation. Thereafter, positions of upper and lower bolt insertion holes of the base part 91 are matched with the upper and lower bolt insertion holes of the plate 7 for stay installation, and a top rail 8 of a handrail is placed on the rail receiver part 93 by a nut by inserting a bolt. Consequently, installation structure of the handrail is simplified, and it is possible to improve outer appearance of the inside of the balcony.