diff --git a/src/OpenMesh/Core/IO/reader/STLReader.cc b/src/OpenMesh/Core/IO/reader/STLReader.cc
index 96d92672..0134e713 100644
--- a/src/OpenMesh/Core/IO/reader/STLReader.cc
+++ b/src/OpenMesh/Core/IO/reader/STLReader.cc
@@ -336,6 +336,8 @@ read_stlb(const std::string& _filename, BaseImporter& _bi) const
     --nT;
   }
 
+  fclose(in);
+
   return true;
 }