In this report, the techniques of successive approximation of the multiple regression analysis are discussed, and are applied to the estimation of aerodynamic derivatives from flight test data by the equation error method. One of the techniques converts a multi-variate problem into the combination of two-variate problems with respect to each explanatory variable. The other technique converts a multi-variate problem into a three-variate problem, which uses a variable and its estimation value as two explanatory variables. The former is usefull for the simple iterative calculation, and the latter is convenient for understanding about the effect of multicollinearity. As the both techniques can be easily visualized, they are usefull to understand the processes and the physical relations from the data to the estimated results through our eyes.