To understand the nature of the pseudo-Jahn-Teller (JT) effect, an energy component analysis of the total energy was carried out in the ground state of the titled ion radicals by using the MCSCF method with 6-31G(d) basis set. Examination of the energy components comprising in the total energy reveals that in the radicals the stability of a less symmetrical nuclear configuration (C-2v) is attributable commonly to the energy lowering of the internuclear repulsion term and the kinetic and interelectronic repulsion terms due to sigma electrons. These observations are consistent with an expansion of the molecular skeleton brought about by the pseudo-JT distortion. In the triafulvalene anion radical, it is further found that the nuclear-electron attractive and interelectronic repulsive terms due to pi electrons also contribute to the stability of the C-2v, structure. In the pentafulvalene cation and heptafulvalene anion radicals, on the other hand, the interelectronic repulsive and nuclear-electron attractive terms due to pi electrons contribute to the stability of the C-2v structure, respectively. These differences are accounted for in terms of a charge polarization attributed to the migration of pi electrons. Moreover, characteristic electronic properties inherent in the radicals are discussed with much attention to the charge and unpaired spin-density distributions in the distorted C-2v structure.