  Excitation functions of the $^{58}$Ni$(n,p)^{58}$Co$^{m,g}$ reactions were
measured in the energy range from 2 to 15 MeV. The energy dependence of the
isomeric cross-section ratio R=sigma_m/(sigma_m+sigma_g) is deduced from the
measured data. The shape and magnitude of the R(E_n) function are described by
model calculations using a consistent parameter set. Questions of the input
level scheme were solved based on the accurate isomeric ratio measured at low
energy region.
