To simplify and facilitate assembly and disassembly, to enlarge the degree of the freedom of selecting a size, a height and a shape and to improve economicity.

A frame body 3 is formed by mutually connecting the frame members 4 of a prescribed cross-sectional shape provided with a connection hole provided on a position in a fixed length from respective ends 5 through the connection hole by a bidirectional connection tool 8 and the plural frame bodies 3 are connected in a vertical direction through a connection piece 10 provided on the bidirectional connection tool 8. Further, the bidirectional connection tool 8 is provided with a shelf plate receiving piece 11 for receiving a shelf plate to be horizontally disposed and the frame member 4 and the bidirectional connection tool 8 are tightened by a button head small screw 19.