The effect of dry okara on the specific loaf volume of bread was investigated. The addition of dry okara to wheat flour gave desirable effect on the gas production of dough, but induced lowering effect on the loaf volume. In the case of dry okara adding to flour after the gluten formation compared with the adding both of flour and dry okara at the same time, the loaf volume was increased and the hardness of bread crumbs was decreased. In spite of the the high water-holding property of dry okara, the moisture contents of okara bread and control bread were similar after baking. The specific loaf volume of bread was increased and the hardness was decreased by addition of Hiprotch (70% gluten and 30% soy protein) or emulsifier to dough. Moreover, the specific loaf volume showed the same high value as that of control bread by using both of Hiprotch and emulsifier. The sensory evaluation of okara bread became acceptable by using both of the improvementors. Hiprotch had no effect on the bread crumb microstructure. It seems that the change of the microstructure by the addition of emulsifier was due to the depressing of starch gelatinization. Proteins extracts from wheat flour, dry okara and Hiprotch were analyzed by size-exclusion high-performance liquid chromatography. The slight interaction between gluten and okara protein occurred by the addition of Hiprotch. It seems that the soy protein in Hiprotch gave desirable effects on gluten formation in the presence of okara. Therefore, it was suggested that desirable effects of Hiprotch addition on gluten formation increased the loaf volume of bread containing okara.