To provide a system furniture wherein adjacent side plates can be easily connected to each other, and also, the degree of freedom in layout is high.

This system furniture has a plurality of side plates 10, 11 which stand vertically and in parallel so that a distance between the centers may become a specified value, a pair of right and left vertical plates 21, 22 which are firmly tied in a manner to be orthogonal to each other, and a pair of top and bottom horizontal plates 23, 24, and also, is equipped with a connecting box 20 which is formed so that the vertical plates 21, 22 can be joined to the confronted surfaces of the adjacent side plates 10, 11. Then, at least one connecting box 20 is arranged between the confronted surfaces of the adjacent side plates 10, 11, and by flatly fixing the pair of the right and left vertical plates 21, 22 of the connecting box 20 to the confronted surfaces of the side plates 10, 11 which are joined, the adjacent side plates 10, 11 are firmly tied.