To reduce cost required for installing a connecting material of a rack formed by connecting mutual column materials of a vertical frame for divisions by the connecting material.

The column material 6 of the vertical frame for the respective divisions is formed in a hollow shape having a front side plate part 11 and both right and left horizontal side plate parts 12 and having the opening rear side. An installation hole 15a capable of inserting a bolt 14 from the inside of the column material 6, is arranged in its front side plate part 11. A through-hole capable of inserting the bolt 14 without rotating the bolt 14, is arranged in a reinforcing seat plate 13. The bolt 14 of a state of projecting from this through-hole checks rotation around the axis by abutment of its head part 19 and the column material 6. The bolt 14 is fitted with a retaining ring 20a pressed in in the axial direction from the tip of a screw shaft part 18a and fixing the bolt 14 in a position allowing the reinforcing seat plate 13 to abut on the column material front side plate part 11, and the connecting material 9 is installed between the reinforcing seat plate 13 and a nut 21 screwed to the bolt 14.