The antifield formalism adapted in the exact renormalization group is found
to be useful for describing a system with some symmetry, especially the gauge
symmetry. In the formalism, the vanishing of the quantum master operator
implies the presence of a symmetry. The QM operator satisfies a simple
algebraic relation that will be shown to be related to the Wess-Zumino
condition for anomalies. We also explain how an anomaly contributes to the QM
operator.Comment: 13 page