The set of criteria for selecting configuration function, presented in the previous paper[2], are extended from double-electron excitation to three-electron exoetation. The effect of other multiplicate states on the excited B 3Πg and A 3Σu++ states are excluded by using the projection operator. By means of CI method the oscillator strongth of the first positiue band system of N2 is calculated. The calculated value is 0.00198, being in good agreement with experimental values.