  The Raman scattering (RS) spectra of rhombohedral $LaMnO_3$ is considered. It
is shown that broad high intensity RS line at 640 $cm^{-1}$ could be explained
in the framework of cooperative dynamical Jahn-Teller effect. This hypothesis
is illustrated through the lattice dynamics calculations explicitly allowing
for the electron-phonon term both in crystal energy and in dynamical matrix.
The averaging scheme for the one mode cooperative dynamical effect is proposed
