To provide a means of settlement wherein the structural and material costs are reduced, and stability for a long period of time, requirements for usage, and a best design requirement can be satisfied.

This sitting furniture is equipped with a seat plate 1 which is approximately horizontally arranged, and legs 5 and 5', 6 and 6' which protrude to the ground. The seat plate has at least two sections 2 and 3 which are laminated and bonded into layers. Those sections comprise a formed plywood which is bonded into layers, and are extended to one section or the whole of the seat plate. The legs 5 and 5', 6 and 6' are equipped with upper extended sections 50 and 50', 60 and 60', and on the lower surface of the upper section 2 facing to the lower section 3, a groove 20 is cut. Then, on the upper surface of the lower section 3 facing to the upper section 2, a groove 30 is formed without being cut. The extended sections 50 and 50', 60 and 60' of the legs 5 and 5', 6 and 6' are inserted in the grooves 20 and 30 between the sections 2 and 3 of the seat plate 1.