  NMR spectra and nuclear spin-lattice relaxation rate $T_1^{-1}$ of $^{11}$B
have been measured in superconducting polycrystalline MgB$_{2}$ with
$T_C^{ons}\cong 39.5K$. It is shown that $(T_{1}T)^{-1}$ and the Knight shift
$K_{s}$ are independent of temperature and nearly isotropic above $T_C$. Both
of these quantities are decreased gradually in going to superconducting state.
According NMR data the density of states (DOS) near the Fermi level is flat at
the scale $\approx$ 500K. Some conclusions on the orbital content of the DOS at
the Fermi level was done and compared with the results of the band structure
calculations.
