  We study how the Chern-Simons term effects the dynamically generated fermion
mass in $(2+1)D$ Quantum Electrodynamics in the framework of large $N$
expansion. We find that when the Chern-Simons term is present half of the
fermions get mass $M+m$ and half get $M-m$. The parity-preserving mass $m$ is
generated only when $N<\tilde{N}_c$. Both the critical number, $\tilde{N}_c$,
of fermion flavor and the magnitude, $m$, reduce when the effect of the
Chern-Simons term dominates.
