  A theory of tunneling conductance spectra for normal
metal/insulator/Sr$_{2}$RuO$_{4}$ junction is studied theoretically. We assume
several types of pair potentials with triplet symmetries that are promising
candidates for Sr$_{2}$RuO$_{4}$. The calculated conductance spectra show
either zero bias peaks or gap like structures depending on the orientations of
the junctions. The existence of a residual components in the gap reflects a
non-unitary property of the superconducting states. Based on the calculation of
a temperature dependence, we will verify that the measurement temperature below
100mK is required to determine the pairing symmetry experimentally.
