On the distribution of bending moment of bracketed structures, various results of investigations based upon the consideration that the brackets were regarded as beams with variable sections have been published. There are, however, few experimental data which justify the investigations of this kind. The authors conducted an experiment using a model of rectangular bracketed structure with different aspect ratios, whereupon it was found that, when the brackets were regarded as beams with variable sections, effective brackets (see Ref. (6)) should be taken into account. On the other hand, introducing the span point (see Ref. (6)), they developed an approximate calculation method by which the distribution of bending moment of bracketed structures could be obtained. The results obtained by this calculation were proved to be in good consistency with those obtained by the experiment.