The adiabatic nuclear potential involving the exchange of at most two pions is derived, the self-pimesic field of each nucleon being taken into account. Numerical values of this potential are calculated. The limit of the applicability of this potential is examined, and as a result it is found that this potential can be used in the region of the inter-nucleon distance x ≳ 0.7 µ−1 (µ−1: pion compton wave length). From the analysis of the two-nucleon phenomena, we find that the quantitative agreement of the theory with experiments is much improved.