We estimate the flux of the GRB neutrino background and compute the event rate at SK and TITAND in the collapsar model , assuming that GRB formation rate is proportional to the star formation rate .
We find that the flux and the event rate depend sensitively on the mass-accretion rate .
Although the detection of signals from GRBs seems to be difficult by SK , we find that we can detect them by TITAND ( optimistically \sim 20 events per year in the energy range E _ { { \overline { \nu } } _ { e } } \geq 50 MeV ) .
Therefore , we show that we will obtain the informations on the mass-accretion rate of collapsar by observing the GRB neutrino background , which , in turn , should give us informations on the total explosion energy of GRBs .