  We study electric transport near the Mott metal-insulator transition. Optical
conductivity of the half-filled Hubbard model on a triangular lattice is
calculated based on a cellular dynamical mean field theory including vertex
corrections inside the cluster. By investigating the spectrum at low
frequencies, we find that a Drude peak on the metallic side smoothly connects
to an "ingap" peak on the insulating side. The optical weight of these peaks
exhibits a critical behavior with power-law near the Mott critical end point,
$|D-D^*|\propto|U-U^*|^{1/\delta}$. We find that the critical exponent
$1/\delta$ differs from the exponents in the thermodynamics.
