  A new method to study the effects of neutrino masses on a supernova neutrino
signal is proposed. The method relies exclusively on the analysis of the full
statistics of neutrino events, it is independent of astrophysical assumptions,
and does not require the observation of any additional phenomenon to trace
possible delays in the neutrino arrival times. A statistics of several
thousands of events as could be collected by SuperKamiokande, would allow to
explore a neutrino mass range somewhat below 1eV.
