diff --git a/optunahub/hub.py b/optunahub/hub.py
index 22913ec..e906bcf 100644
--- a/optunahub/hub.py
+++ b/optunahub/hub.py
@@ -2,6 +2,7 @@
 
 import importlib.util
 import inspect
+import logging
 import os
 import shutil
 import sys
@@ -18,6 +19,10 @@
 from optunahub import _conf
 
 
+# Revert the log level to Python's default (i.e., WARNING) for the `ga4mp` package.
+logging.getLogger("ga4mp.ga4mp").setLevel(logging.WARNING)
+
+
 def _import_github_dir(
     repo_owner: str,
     repo_name: str,