  The theory of inflation will be investigated as well as supersymmetry
breaking in the context of supergravity, incorporating the target-space duality
and the non-perturbative gaugino condensation in the hidden sector. The
inflation and supersymmetry breaking occur at once by the interplay between the
dilaton field as inflaton and the condensate gauge-singlet field. The model
satisfies the slow-roll condition which solves the eta-problem. When the
particle rolls down along the minimized trajectry of the potential V(S,Y) at a
duality invariant fixed point T=1, we can obtain the e-fold value \sim 57. And
then the cosmological parameters obtained from our model well match with the
recent WMAP data combined with other experiments. This observation is
suggesting to consider the string-inspired supergravity as the fundamental of
the theory of the evolution of the universe as well as the particle theory.
