  We examine a large N duality via geometric transition for N=1 SO/Sp gauge
theories with superpotential for adjoint chiral superfield. In this paper, we
find that the large N gauge theories are exactly analyzed for the classical
quartic superpotentials by the finite rank SO/Sp gauge theories. With this
classical superpotentials, we evaluate the confining phase superpotentials
using the Seiberg-Witten theory. In the dual theory, we calculate the
superpotential generated by the R-R and NS-NS 3-form fluxes. As the non-trivial
examples, we discuss for SO(6), SO(8) and Sp(4) gauge theories. In these cases
we have the perfect agreement of the confining phase superpotentials up to the
4th order of the glueball superfields.
