diff --git a/metric/prometheus.go b/metric/prometheus.go
index 6288c67..89b3848 100644
--- a/metric/prometheus.go
+++ b/metric/prometheus.go
@@ -135,7 +135,11 @@ func (pe *prometheusExporter) loop(ctx context.Context) {
 			}
 
 			if err := prometheus.Register(nextcollector); err != nil {
-				logger.Error("prometheus register err :", *nm, err)
+				if _, ok := err.(prometheus.AlreadyRegisteredError); ok {
+					// 이미 등록된 metric. child process를 여럿 실행하면 발생됨
+				} else {
+					logger.Error("prometheus register err :", *nm, err)
+				}
 			} else {
 				collector = nextcollector
 			}