To easily perform highly accurate installation work of a guard rail placed on a floor face on a passage side of a shelf.

In the guard rail 2, a plurality of rail members 9a, 9b having vertical plate parts 11 vertically erected with respect to the floor face are installed on the floor face on the passage side of the shelf 1 along the shelf 1 with the vertical plate parts 11 continued to the rail member length direction. At a connection portion between the rail members 9a, 9b, surface mating plate materials 15, 16 having tip portions protruded toward the rail members 9b, 9a on the other side are placed on back faces 11a on the shelf side of the vertical plate parts 11 of the rail members 9a, 9b on both sides, so as to have different mounting heights to prevent overlapping. The protruded parts 15b, 16b of the surface mating plate materials 15, 16 of the rail members 9a, 9b on both sides are made abut on the back faces 11a on the shelf side of the vertical plate parts 11 of the rail members 9a, 9b on the other side, respectively.