diff --git a/tool/NumberListParser.h b/tool/NumberListParser.h
index 60bb2cfa..6cf0dd16 100644
--- a/tool/NumberListParser.h
+++ b/tool/NumberListParser.h
@@ -36,7 +36,7 @@ class NumberListParser
 {
     public:
         NumberListParser();
-        ~NumberListParser();
+        virtual ~NumberListParser();
 
         typedef list<unsigned int> NumberList;