  We study deformations of dualities in finite N=2 supersymmetric QCD. Adding
mass terms for some quarks and the adjoint matter to the finite N=2 theory,
which is known to have dual descriptions, the correspondence of gauge invariant
operators between the original and dual theory is deformed. As a result, we
naturally obtain N.Seiberg's N=1 duality. Furthermore, we discuss the origin of
the meson and superpotential in the dual theory. This approach can be applied
to SU(N), SO(N), and USp(2N) gauge theories, and we analyze all these cases.
