PURPOSE: To provide a bracket for medium duty fiberboard used for forming a cabinet made of the medium duty fiberboards, a structure made of the medium duty fiberboards, the joining method of the medium duty fiberboards and a cabinet, which can be formed out of the medium duty fiberboards.

CONSTITUTION: The brackets has side plate parts 25a and 25b, which abut against the side faces of medium duty fiberboards, bolt fixing parts 28, which are formed on the side plate parts 25a and 25b and to which bolts B passing through the through holes of the medium duty fiberboards, and fastening parts 26a and 26b, which are formed integrally with the side plate parts 25a and 25b and fasten the side edge faces in the load applying directions of the medium duty fiberboards so as to keep the bolt positions in the through holes when load is applied to the medium duty fiberboards.