diff --git a/thread_pool.hpp b/thread_pool.hpp
index 914ba01..8652de1 100644
--- a/thread_pool.hpp
+++ b/thread_pool.hpp
@@ -195,5 +195,6 @@ void thread_pool::loop()
             queue.pop_front();
         }
         fun();
+        fun = nullptr;
     }
 }