The influence of impurity atoms into energy of increasing cubic iron nanocluster upon joining of the additional iron atom from the environment was studied by the method of molecular mechanics using Lennard-Jones potential. We established that the energy of the system depends on the mutual arrangement of impurity atoms and additional iron atom in increasing cluster. Were calculated most energetically favorable configurations of iron atom, which correspond to increasing of the nanocluster because of adhesion. The conditions of stability of the FCC nanocluster as to an influence of the interstitial and substitutional impurities were estimated.The study could be useful for nanoclusters designing for a medicine, biology and NEMS.