  We report the temperature-dependent three-dimensional angle-resolved
photoemission spectra of the Kondo semiconductor SmB$_6$. We found a difference
in the temperature dependence of the peaks at the X and $\Gamma$ points, due to
hybridization between the Sm 5d conduction band and the nearly localized Sm 4f
state. The peak intensity at the X point has the same temperature dependence as
the valence transition below 120 K, while that at the $\Gamma$ point is
consistent with the magnetic excitation at Q=(0.5,0.5,0.5) below 30 K. This
suggests that the hybridization with the valence transition mainly occurs at
the X point, and the initial state of the magnetic excitation is located at the
$\Gamma$ point.
