diff --git a/src/sm_tias_lightsim/evaluation/visualize.py b/src/sm_tias_lightsim/evaluation/visualize.py
index 7b5c3a5..36d3265 100644
--- a/src/sm_tias_lightsim/evaluation/visualize.py
+++ b/src/sm_tias_lightsim/evaluation/visualize.py
@@ -18,6 +18,7 @@
 # このモジュール内では matplotlib.use() を pyplot import より前に置く．
 matplotlib.use("Agg")
 
+import matplotlib.figure  # noqa: E402
 import matplotlib.patches  # noqa: E402
 import matplotlib.pyplot as plt  # noqa: E402
 import numpy  # noqa: E402