Recently, as to the causes of microangiopathy peculiar to diabetes, blood flow shows a tendency to be of great importance. In 23 cases of guinea pig studies using statistical techniques, we attained the following results regarding the correlations between velocity of the blood flow in the radiating artery of cochlea and plasma glucose level, serum total protein, hematocrit respectively. (1) The table of correlation matrix shows a significant correlation between plasma glucose level and velocity of the blood flow (P<0.05). (2) In 17 cases having less than 300mg/dl of plasma glucose level, we conducted multiple regression analysis to calculate velocity of the blood flow with the three predictor variables: plasma glucose level, serum total protein, and hematocrit. The coefficient of determination showed 69%. As we have seen, the plasma glucose level has the greatest effect on the blood flow velocity among the three variables: the plasma glucose level, the serum total protein, and the hematocrit in the group having less than 300mg/dl of plasma glucose level in carotid artery.