Economic value added (EVA) is introduced on two levels: as index for evaluation of corporation and as index for evaluation of business unit. In the latter case, application of one and the same cost of capital to all business units of a business corporation may be possible, but it is a fundamental policy for EVA to apply different cost of capital to business units with different risks. Estimate of cost of capital of business units is a problem to be resolved. The author, focusing on the question of the estimate of cost of capital of business units, has conducted a demonstrative study on risk structure of cost of capital estimates by using financial indices of Japanese manufacturers (37 automotive industries, 141 electrical and electronic machinery industries, 63 food processing industries, 98 chemical industries, 125 general machinery industries) for a period of 5 years from 1995 to 1999. The author presumes that $eta$ is explained by a regression formula ${eta}=B_0+{Sigma}B_iY_i+{alpha}$ ($Y_i$: financial indices) and selects 40 explanatory variables from financial statements as risk components. Using their financial indices, the author concludes through a series of statistical analyses that there is a good likelihood of estimating cost of capital for Japanese industries and is convinced that it will lead to more reliable and practical results by assigning averages and variances to 40 primary financial indices for a period of 3 to 5 years selected in this demonstrative study.