  Dielectric responces of the one-dimentional electron system is investigated
numerically. We treat an interacting one-dimentional spinless fermion model
with disorder by using the Density Matrix Renormalization Group(DMRG) method
which is extended for nonuniform systems. We apply an electric field $E$ to the
system and calculate dielectric responces. Dielectric responce of the Mott
insulator and the Anderson insulator are calculated respectively. Steplike
behaviors in $P-E$ curve are obtained which corresponds to breakdown of the
insulating behavior. For the Mott insulator, the steps originate from
generation of kink-pairs. For the Anderson insulator on the other hand, the
origin of the steps is a crossing of the localized one particle energy levels.
We also treat random systems with interaction. From one parameter scaling
analysis of the susceptibility $\chi$, the metal-insulator transition in
attractively interacting region is confirmed and a phase diagram of the random
spinless fermion model is obtained.
