  On the basis of the Ward-Pitaevskii identity, the residual resistivity
$\rho_{0}$ is shown to exhibit huge enhancement around the quantum critical
point of valence transition in Ce-based heavy electron systems. This explains a
sharp peak of $\rho_{0}$ observed in CeCu$_2$Ge$_2$ under the pressure at
$P\sim$16GPa where the superconducting trasition temperature also exhibit the
sharp peak.

Strongly Correlated Electrons;Superconductivity