[en] On the base of the Green function method as applied to the S matrix and microscopic theory of the optical potential, the S-neutron strength function is investigated in the maximum range of 40 <= A <= 60. The scattered S-neutron energy 0.1 MeV. The optical potential is averaged over the energy range of 2 MeV. The width GITAsub(s), shift Δsub(s) and the strength function SFsub(0) of the S-neutron state are determined. The radial dependences of the imaginary and real parts of the optical potential for Ca and Ni isotopes are presented. The strength function of S-neutrons of 1f-shell nuclei is also shown. The S-neutron state is considerably shifted from the resonance 3sub(s sub(1/2)) due to the effect of the input states of a compound nucleus. The width GITAsub(s) of a Ca nucleus is determined by the input states 2p-1h, while that of Cr, Fe, Ni nuclei is determined by collective input states. The shift Δsub(s) is determined totally by the 2p-1h states in all nuclei. It is concluded that the neutron strength function can be sufficiently well described within the optical model accounting for specific features of a scattering nucleus