diff --git a/requirements.txt b/requirements.txt
index 48caf01..40fa629 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,7 +3,7 @@ myst-parser==4.0.1
 rcssmin==1.2.2
 rjsmin==1.2.5
 shibuya==2025.12.19
-sphinx==8.2.3
+sphinx==9.0.4
 sphinx-contributors==0.2.7
 sphinx-copybutton==0.5.2
 sphinx-design==0.6.1