To provide a floor device which minimizes the number of bearing portions to be borne by a fixed portion, saves the entire weight thereof, ensures sufficient strength, and facilitates disassembly or removal thereof.

The floor device is comprised of a plurality of truss bodies 11 each consisting of an upper transverse member 12 and a lower transverse member 13 which are formed like shapes, and a plurality of joint members 24 arranged between the transverse members 12, 13. Each truss body 11 is borne by the fixed portion 5 via bearing means 51 arranged on both ends thereof, and the truss bodies 11 thus formed are arranged at intervals L. Then a plurality of beam bodies 71 are laid between the truss bodies 11, and a floor surface 92a is arranged above the truss bodies and the beam bodies. Thus the number of the bearing portions to be borne by the fixed portion is minimized, and vibrations transmitted to the floor surface are absorbed by the truss bodies, whereby sound insulating effect of the floor device can be expected. Further by constituting each truss body of the lower and upper transverse members which are formed like the shapes, and the joint members, the entire weight of the floor device is reduced, and the sufficient strength is ensured.