  We have analyzed about 100 voltage-dependent differential resistance dV/dI(V)
curves of metallic point contacts between c-axis oriented MgB$_2$ thin film and
Ag, which exhibit clear Andreev reflection features connected with the
superconducting gap. About one half of the curves show the presence of a second
larger gap. The histogram of the double-gap distribution reveals distinct
maxima at 2.4 and 7 meV, while curves with a single-gap features result in more
broad maximum at 3.5 meV. The double-gap distribution is in qualitative
agreement with the distribution of gap values over the Fermi surface calculated
by H. J. Choi et al. (cond-mat/0111183). The data unequivocally show the
presence of two gaps $\Delta_{S}=2.45\pm 0.15$ meV and $\Delta_{L}=7.0\pm 0.45$
meV in MgB$_2$ with gap ratio $2.85\pm 0.15$. Our observations prove further a
widely discussed multi-gap scenario for MgB$_2$, where two distinct gaps are
seen in the clean limit, while a single averaged gap is present in the dirty
one.
