diff --git a/src/dynamic_graph/signal_base.py b/src/dynamic_graph/signal_base.py
index 109cf20360ce61775f96debb658e27eff36c5191..66e48359bab9c6fc3ae54566e666dab820ea64db 100644
--- a/src/dynamic_graph/signal_base.py
+++ b/src/dynamic_graph/signal_base.py
@@ -160,9 +160,9 @@ class SignalBase (object) :
         """
         if obj :
             self.obj = obj
-        if not self.obj :
-            self.obj = wrap.create_signal_base(self, name)
-
+        else :
+            raise RuntimeError(
+                "A pointer is required to create SignalBase object.")
     @property
     def time(self) :
         """