In this study, the principle of structural analysis by the ε-method was investigated for three-dimensional multistoried and multispan rigid frames loaded vertically or horizontally, in cases where the bases of the columns of a rigid frame were all fixed. The ε-method is one of the slope-deflection methods and is of practical use in the structural analysis of rigid frames. An example of a digital computing program for these analysis was constructed on the basis of the ε-method and various quantities were computed through this program. The results calculated by this digital computing program are shown. Finally, these results are compared with the ones obtained by the finite-element method, and the effectiveness of applying the ε-method to the cases of three-dimensional rigid frames is confirmed.