  An accurate treatment of Coulomb breakup reactions is presented by using both
the Gaussian expansion method and the method of continuum discretized coupled
channels. As $L^2$-type basis functions for describing bound- and
continuum-states of a projectile, we take complex-range Gaussian functions,
which form in good approximation a complete set in a large configuration space
being important for Coulomb-breakup processes. Accuracy of the method is tested
quantitatively for $^{8}{\rm B}+^{58}$Ni scattering at 25.8 MeV.
