The fundamental studies on the quantitative correction procedures of the ion probe microanalysis based on the Saha-Eggert equation have been made to examine then validity and to develop an appropriate minimum seeking method. The correction procedures were checked by applying them to the analysis of a standard sample of known concentration. The agreement between the calculated and themical concentrations is generally good. The accuracy of the quantitative analysis is discussed in terms of the degree of ionization as a function of both the temperature and electron density which are calculated from the Saha-Eggert equation.