diff --git a/mace/core/net.cc b/mace/core/net.cc
index f629e2068da0015a3744aa6a4b2ecc6c309e3739..ea5ea504b6019fc35e930d69addcd5af502c76d0 100644
--- a/mace/core/net.cc
+++ b/mace/core/net.cc
@@ -43,7 +43,7 @@ SerialNet::SerialNet(const std::shared_ptr<const OperatorRegistry> op_registry,
     // TODO(liuqi): refactor based on PB
     const int op_device =
         ArgumentHelper::GetSingleArgument<OperatorDef, int>(
-            operator_def, "device", -1);
+            operator_def, "device", static_cast<int>(device_type_));
     if (op_device == type) {
       VLOG(3) << "Creating operator " << operator_def.name() << "("
               << operator_def.type() << ")";
diff --git a/mace/core/workspace.cc b/mace/core/workspace.cc
index 3867cfe36f3b5606f793de0043cda6fad79429f6..46ae0b48a49aa461fb0efee21826a8bd5fc443aa 100644
--- a/mace/core/workspace.cc
+++ b/mace/core/workspace.cc
@@ -139,7 +139,7 @@ void Workspace::CreateOutputTensorBuffer(const NetDef &net_def,
     // TODO(liuqi): refactor based on PB
     const int op_device =
         ArgumentHelper::GetSingleArgument<OperatorDef, int>(
-            op, "device", -1);
+            op, "device", static_cast<int>(device_type));
     if (op_device == device_type && !op.mem_id().empty()) {
       const DataType op_dtype = static_cast<DataType>(
           ArgumentHelper::GetSingleArgument<OperatorDef, int>(
@@ -175,7 +175,7 @@ void Workspace::CreateOutputTensorBuffer(const NetDef &net_def,
     // TODO(liuqi): refactor based on PB
     const int op_device =
         ArgumentHelper::GetSingleArgument<OperatorDef, int>(
-            op, "device", -1);
+            op, "device", static_cast<int>(device_type));
     if (op_device == device_type && !op.mem_id().empty()) {
       auto mem_ids = op.mem_id();
       int count = mem_ids.size();