  Under the assumption of Abelian dominance in QCD, we show that either color
charge or chirality of quark is not conserved, when the low energy massless
quark collides with QCD monopole. Because the color charge is conserved in
reality, the chirality is not conserved. We show by using chiral anomaly that
chiral non symmetric quark pair production takes place when a classical color
charge is putted in a vacuum with monopole condensation, while chiral symmetric
pair production takes place in a vacuum with no monopole condensation. Our
results indicate that the chiral symmetry is broken by the monopole
condensation.
