diff --git a/STL_Extension/include/CGAL/array.h b/STL_Extension/include/CGAL/array.h
index 1693c6994e8..cfaca0a0550 100644
--- a/STL_Extension/include/CGAL/array.h
+++ b/STL_Extension/include/CGAL/array.h
@@ -61,7 +61,7 @@ struct Construct_array
   template <typename T, typename... Args>
   constexpr
   std::array<T, 1 + sizeof...(Args)>
-  operator()(const T& t, const Args& ... args)
+  operator()(const T& t, const Args& ... args) const
   {
     return make_array (t, args...);
   }