diff --git a/mace/core/net.cc b/mace/core/net.cc
index d914226e8b906db39c1437b9f2c751eccfc0f460..c5877f4a2cb08eddafd7eec42fea7fe52e5ed5d2 100644
--- a/mace/core/net.cc
+++ b/mace/core/net.cc
@@ -23,7 +23,7 @@ SimpleNet::SimpleNet(const std::shared_ptr<const NetDef>& net_def,
     std::unique_ptr<OperatorBase> op{nullptr};
     OperatorDef temp_def(operator_def);
     op = CreateOperator(temp_def, ws, type);
-    if (!op) {
+    if (op) {
       operators_.emplace_back(std::move(op));
     }
   }