  We examine the optical conductivity \sigma(\omega) and the chemical potential
\mu, together with the spin correlation, in the strong-coupling limit of a
hole-doped two-dimensional triangular Hubbard model near half filling by using
an exact diagonalization technique. In contrast to the case of a square lattice
without frustration, the doping dependences of \mu and the Drude weight
indicate that the charge degree of freedom is weakly coupled to the spin degree
of freedom. However, we find that \sigma(\omega) shows strong incoherent
excitations extended to a higher energy region. This implies that geometrical
frustration in strongly correlated electron systems influences incoherent
charge dynamics.
