To provide a light weight, high strength bamboo structural board allowing easy assembly with a simple structure.

A hollow structured bamboo board is composed by using a plurality of cleaved bamboo materials as a structural member, arranging them parallel and mutually spaced in thickness direction and holding them in parallel posture with top- and bottom-plates; provided that top- and bottom-plates (12) are composed of a plate material in which substantially flat bamboo materials cleaved in uniform width are arranged flat and parallel so that their side edges may mutually adjoin and cemented or fixed while cleaved bamboo materials of structural member (11) are cleaved in uniform width to make narrow strips; and that the plate is arranged so that its cleaved bamboo material and the cleaved bamboo material of a structural member may be orthogonal. A plate (12') may also be composed by caking wood chips, wood flour or bamboo flour in plate by a synthetic resin. Further, a plate (12'') may be composed of a corrugated resin cardboard to make its corrugation and the structural member orthogonal.