  Assume that $M$ is a smooth manifold with a symplectic structure $\omega$.
Then Weyl manifolds on the symplectic manifold $M$ are Weyl algebra bundles
endowed with suitable transition functions. From the geometrical point of view,
Weyl manifolds can be regarded as geometrizations of star products attached to
$(M,\omega)$. In the present paper, we are concerned with the automorphisms of
the Weyl manifold corresponding to Poincar\'e-Cartan class ($c_0$ is a
$\check{\rm C}$ech cocycle corresponding to the symplectic structure $\omega$.)
$[c_0+\sum_{\ell=1}^\infty c_{\ell} \nu^{2\ell}]\in \check{H}^2 (M)[[\nu^2]]$.
We also construct modified contact Weyl diffeomorphisms.
