diff --git a/l10n/zh-TW/viewer.properties b/l10n/zh-TW/viewer.properties
index ca230e3eb..d38904381 100644
--- a/l10n/zh-TW/viewer.properties
+++ b/l10n/zh-TW/viewer.properties
@@ -57,6 +57,11 @@ page_rotate_ccw.title=逆時針旋轉
 page_rotate_ccw.label=逆時針旋轉
 page_rotate_ccw_label=逆時針旋轉
 
+hand_tool_enable.title=啟動掌型工具
+hand_tool_enable_label=啟動掌型工具
+hand_tool_disable.title=停用掌型工具
+hand_tool_disable_label=停用掌型工具
+
 # Tooltips and alt text for side panel toolbar buttons
 # (the _label strings are alt text for the buttons, the .title strings are
 # tooltips)