Adopting the new method of the theory of nuclear forces proposed by one of us (M.T) and others, the deuteron ground state and low energy neutron-proton scattering have been investigated. The symmetrical pseudoscalar π-meson potentials including second- and fourth-order terms are assumed in the outside region, while in the inside region where the static meson potential becomes meaningless, phenomenological potentials represented by square well are adopted. It is shown that we can then account for the experimental data, if we take the value 0.09 ∼ 0.10 as the magnitude of the coupling constant between π-meson and nucleon. Saturation does not result from these potentials in the static approximation.