We construct a three-dimensional topological sigma model which is induced
from a generalized complex structure on a target generalized complex manifold.
This model is constructed from maps from a three-dimensional manifold X to an
arbitrary generalized complex manifold M. The theory is invariant under the
diffeomorphism on the world volume and the b-transformation on the
generalized complex structure. Moreover the model is manifestly invariant under
the mirror symmetry. We derive from this model the Zucchini's two dimensional
topological sigma model with a generalized complex structure as a boundary
action on ∂X. As a special case, we obtain three dimensional
realization of a WZ-Poisson manifold.Comment: 18 page