DOUBLE FLOOR

PROBLEM TO BE SOLVED: To form a gap between floor boards via very easy execution by bringing contact sections provided at the tip sections of butted corner sections of the floor boards into contact with the central member of a floor board support. SOLUTION: A floor board support 12 constituted of a pedestal 18, a column body 19, a bearer 20, a central member 21, and a cap 22 is mounted on a floor face 13, floor boards 11, 11 are arranged on it, and the butt corner sections of the floor boards 11 are supported by the floor board support 12. Contact sections 16, 16 are provided at the tip sections of the butt corner sections, and hook sections 17, 17 are formed at the downward portions of the tips. The floor boards 11 are mounted on the bearer 20 so that the hook sections 17 are hooked on the outside annular ring body 35 of the central member 21. The contact sections 16 are brought into contact with the central member 21, and the prescribed gap 39 is formed between the floor boards 11.