[en] In the framework of the nonlocal quark model the mass splitting of baryons is studied. Lagrangians of interaction between quarks and physical fields are invariant with respect to the SU(3)-group. SU(3)-symmetry breaking is taking into account by the change of parameters of a strange quark. A good fit to experimental data is obtained. All formulae are stable with respect to changing quark parameters. It turned out that the effective constant of the perturbation expansion is less than unity. The calculation technique of physical processes with the participation of baryons is developed