Batch cryptography has been developed into two main branches - batch verification and batch identification. Batch verification is a method to determine whether a set of signatures contains invalid signatures, and batch identification is a method to find bad signatures if a set of signatures contains invalid signatures. Recently, some significant developments appeared in such field, especially by Ferrara et al.  and Law et al. , respectively. However, no batch identification method for group signa-ture have been suggested. In this paper, by exploiting earlier works on standard signature schemes, we propose methods of batch verification and batch identification of a group signature scheme.