The low-energy breakup differential cross sections of the neutron-deuteron (nd) scattering are studied employing the energy-independent version of the quark-model baryon-baryon interaction fss2. This interaction reproduces almost all the breakup differential cross sections predicted by the meson-exchange potentials for neutron incident energies E n ≤ 65 MeV. The space star anomaly of 13 MeV nd scattering is not improved even in our model. Some overestimation of the breakup differential cross sections at E n = 22.7 -65 MeV implies that systematic studies of various breakup configurations are necessary both experimentally and theoretically.Subject Index: 200, 205 §1. IntroductionThe three-nucleon (3N ) system is appropriate to study the underlying nucleonnucleon (NN ) interaction, since many techniques for solving the system exactly are well developed nowadays. 1), 2) Ample experimental data have already been accumulated especially for the low-energy neutron-deuteron (nd) and proton-deuteron (pd) scattering, and extensive studies to detect the 3N force have been carried out on the basis of modern meson-exchange potentials, 3), 4) and more recently, of the chiral effective field theory. 5), 6) Most research studies in such a direction are concerned with energies higher than 100 MeV for the nucleon incident energy E n in a laboratory (lab) system, since the 3N force effect is expected to be revealed prominently at high energies. 3) On the other hand, the discrepancies in various 3N observables between the theory and the experiment in the E n ≤ 65 MeV region are not resolved even with the recent accurate treatment of the Coulomb force. 7)-9) This is particularly true for nucleon-induced deuteron breakup processes. It is therefore worthwhile to reexamine the NN interaction itself if the present-day realistic force is the most appropriate one to start with.In previous studies, 10), 11) referred to as I and II hereafter, we have applied the quark-model (QM) baryon-baryon interaction fss2 to the problems of neutrondeuteron (nd) elastic scattering. This interaction model fss2 describes available NN data in a comparable accuracy with the modern meson-exchange potentials. 12) By eliminating the inherent energy dependence of the resonating-group kernel, fss2 was found to yield a nearly correct triton binding energy, S-wave nd scattering lengths and low-energy eigenphase shifts without introducing the 3N force. 13), 14) The predicted elastic differential cross sections have sufficiently large cross section