  The tunnel conductance in normal-metal / insulator / PrOs$_4$Sb$_{12}$
junctions is theoretically studied, where skutterudite PrOs$_4$Sb$_{12}$ is
considered to be an unconventional superconductor. The conductance are
calculated for several pair potentials which have been proposed in recent
works. The results show that the conductance is sensitive to the relation
between the direction of electric currents and the position of point nodes. We
also show that the conductance spectra often deviate from the shape of the bulk
density of states and that the sub gap spectra have peak structures in the case
of the spin-triplet pair potentials. The results indicate that the tunnel
conductance is a useful tool to obtain an information of the pairing symmetry.
