In the field of commercial capital theory, recently Yano (2006) and Murakami (2014) have tried to incorporate the commercial sector into the reproduction scheme. However, Yano's formulation put the commercial capital outside the reproduction formula, and his explanation is too complex. Moreover, Murakami’s formation still has a problem owing to his methodology that uses only the numerical examples. Therefore, this paper incorporates the commercial sector into the reproduction scheme as a perfect equation system based on the equalized profit rate. It is because equalized profit rate is also applied to the commercial sector to determine its weight in the whole economy. As a result of these calculations, this paper also identified that average profit rate is determined by the technological conditions only in the industrial sectors.