Evolution of a cluster of primordial black holes in the two-body relaxation approximation based on the Fokker-Planck equation is discussed. In our calculation, we consider the self-gravitating cluster with a wide range of black holes masses from $10^{-4} M_{odot}$ up to $100 M_{odot}$ and the total mass $10^5 M_{odot}$. Moreover, we included a massive black hole in the cluster center which determines the evolution rate of the density profile in its vicinity.