diff --git a/dist/index.html b/dist/index.html
index 49d0e8b..d061bbc 100644
--- a/dist/index.html
+++ b/dist/index.html
@@ -87,7 +87,8 @@ <h4>Example URI</h4><div class="definition"><span class="method get">GET</span>&
     "<span class="hljs-attribute">order_point_quantity</span>": <span class="hljs-value"><span class="hljs-string">"5"</span>
   </span>}</span>,
   "<span class="hljs-attribute">created_at</span>": <span class="hljs-value"><span class="hljs-string">"2018-03-27T09:38:19+09:00"</span></span>,
-  "<span class="hljs-attribute">updated_at `2018-03-27T09:38:19+09:00`</span>": <span class="hljs-value"><span class="hljs-string">""</span></span>,
+  "<span class="hljs-attribute">updated_at</span>": <span class="hljs-value"><span class="hljs-string">"2018-03-27T09:38:19+09:00"</span></span>,
+  "<span class="hljs-attribute">update_date</span>": <span class="hljs-value"><span class="hljs-string">"2018-03-27T09:38:19+09:00"</span></span>,
   "<span class="hljs-attribute">create_user_name</span>": <span class="hljs-value"><span class="hljs-string">"田村 太郎"</span></span>,
   "<span class="hljs-attribute">update_user_name</span>": <span class="hljs-value"><span class="hljs-string">"田村 次郎"</span></span>,
   "<span class="hljs-attribute">user_group</span>": <span class="hljs-value"><span class="hljs-string">"基本グループ"</span></span>,
@@ -217,9 +218,13 @@ <h4>Example URI</h4><div class="definition"><span class="method get">GET</span>&
       "<span class="hljs-attribute">type</span>": <span class="hljs-value"><span class="hljs-string">"string"</span></span>,
       "<span class="hljs-attribute">description</span>": <span class="hljs-value"><span class="hljs-string">"作成日（ISO 8601形式）"</span>
     </span>}</span>,
-    "<span class="hljs-attribute">updated_at `2018-03-27T09:38:19+09:00`</span>": <span class="hljs-value">{
+    "<span class="hljs-attribute">updated_at</span>": <span class="hljs-value">{
       "<span class="hljs-attribute">type</span>": <span class="hljs-value"><span class="hljs-string">"string"</span></span>,
-      "<span class="hljs-attribute">description</span>": <span class="hljs-value"><span class="hljs-string">"更新日（ISO 8601形式）"</span>
+      "<span class="hljs-attribute">description</span>": <span class="hljs-value"><span class="hljs-string">"システム更新日時（ISO 8601形式）。在庫データに関連するあらゆる変更で自動更新される"</span>
+    </span>}</span>,
+    "<span class="hljs-attribute">update_date</span>": <span class="hljs-value">{
+      "<span class="hljs-attribute">type</span>": <span class="hljs-value"><span class="hljs-string">"string"</span></span>,
+      "<span class="hljs-attribute">description</span>": <span class="hljs-value"><span class="hljs-string">"更新日時（ISO 8601形式）。基本的にシステム更新日時と同様だが、入出庫予定の変更や追加項目自体の追加・削除など在庫データ自体の変更ではない場合は更新されない"</span>
     </span>}</span>,
     "<span class="hljs-attribute">create_user_name</span>": <span class="hljs-value">{
       "<span class="hljs-attribute">type</span>": <span class="hljs-value"><span class="hljs-string">"string"</span></span>,
@@ -599,7 +604,8 @@ <h4>Example URI</h4><div class="definition"><span class="method get">GET</span>&
     "<span class="hljs-attribute">order_point_quantity</span>": <span class="hljs-value"><span class="hljs-string">"5"</span>
   </span>}</span>,
   "<span class="hljs-attribute">created_at</span>": <span class="hljs-value"><span class="hljs-string">"2018-03-27T09:38:19+09:00"</span></span>,
-  "<span class="hljs-attribute">updated_at `2018-03-27T09:38:19+09:00`</span>": <span class="hljs-value"><span class="hljs-string">""</span></span>,
+  "<span class="hljs-attribute">updated_at</span>": <span class="hljs-value"><span class="hljs-string">"2018-03-27T09:38:19+09:00"</span></span>,
+  "<span class="hljs-attribute">update_date</span>": <span class="hljs-value"><span class="hljs-string">"2018-03-27T09:38:19+09:00"</span></span>,
   "<span class="hljs-attribute">create_user_name</span>": <span class="hljs-value"><span class="hljs-string">"田村 太郎"</span></span>,
   "<span class="hljs-attribute">update_user_name</span>": <span class="hljs-value"><span class="hljs-string">"田村 次郎"</span></span>,
   "<span class="hljs-attribute">user_group</span>": <span class="hljs-value"><span class="hljs-string">"基本グループ"</span></span>,
@@ -788,9 +794,13 @@ <h4>Example URI</h4><div class="definition"><span class="method get">GET</span>&
       "<span class="hljs-attribute">type</span>": <span class="hljs-value"><span class="hljs-string">"string"</span></span>,
       "<span class="hljs-attribute">description</span>": <span class="hljs-value"><span class="hljs-string">"作成日（ISO 8601形式）"</span>
     </span>}</span>,
-    "<span class="hljs-attribute">updated_at `2018-03-27T09:38:19+09:00`</span>": <span class="hljs-value">{
+    "<span class="hljs-attribute">updated_at</span>": <span class="hljs-value">{
       "<span class="hljs-attribute">type</span>": <span class="hljs-value"><span class="hljs-string">"string"</span></span>,
-      "<span class="hljs-attribute">description</span>": <span class="hljs-value"><span class="hljs-string">"更新日（ISO 8601形式）"</span>
+      "<span class="hljs-attribute">description</span>": <span class="hljs-value"><span class="hljs-string">"システム更新日時（ISO 8601形式）。在庫データに関連するあらゆる変更で自動更新される"</span>
+    </span>}</span>,
+    "<span class="hljs-attribute">update_date</span>": <span class="hljs-value">{
+      "<span class="hljs-attribute">type</span>": <span class="hljs-value"><span class="hljs-string">"string"</span></span>,
+      "<span class="hljs-attribute">description</span>": <span class="hljs-value"><span class="hljs-string">"更新日時（ISO 8601形式）。基本的にシステム更新日時と同様だが、入出庫予定の変更や追加項目自体の追加・削除など在庫データ自体の変更ではない場合は更新されない"</span>
     </span>}</span>,
     "<span class="hljs-attribute">create_user_name</span>": <span class="hljs-value">{
       "<span class="hljs-attribute">type</span>": <span class="hljs-value"><span class="hljs-string">"string"</span></span>,
@@ -5679,7 +5689,7 @@ <h4>Example URI</h4><div class="definition"><span class="method post">POST</span
       "<span class="hljs-attribute">description</span>": <span class="hljs-value"><span class="hljs-string">"エラー内容"</span>
     </span>}
   </span>}
-</span>}</code></pre><div style="height: 1px;"></div></div></div></div></div></section></div></div></div><p style="text-align: center;" class="text-muted">Generated by&nbsp;<a href="https://github.com/danielgtaylor/aglio" class="aglio">aglio</a>&nbsp;on 04 Feb 2026</p><script>/* eslint-env browser */
+</span>}</code></pre><div style="height: 1px;"></div></div></div></div></div></section></div></div></div><p style="text-align: center;" class="text-muted">Generated by&nbsp;<a href="https://github.com/danielgtaylor/aglio" class="aglio">aglio</a>&nbsp;on 18 Feb 2026</p><script>/* eslint-env browser */
 /* eslint quotes: [2, "single"] */
 'use strict';
 
diff --git a/includes/api/inventories.md b/includes/api/inventories.md
index 006d07e..15389a3 100644
--- a/includes/api/inventories.md
+++ b/includes/api/inventories.md
@@ -250,7 +250,8 @@
 + quantity_management_attributes
   + order_point_quantity: 5 (string) - 発注点
 + created_at: `2018-03-27T09:38:19+09:00` (string) - 作成日（ISO 8601形式）
-+ updated_at `2018-03-27T09:38:19+09:00` (string) - 更新日（ISO 8601形式）
++ updated_at: `2018-03-27T09:38:19+09:00` (string) - システム更新日時（ISO 8601形式）。在庫データに関連するあらゆる変更で自動更新される
++ update_date: `2018-03-27T09:38:19+09:00` (string) - 更新日時（ISO 8601形式）。基本的にシステム更新日時と同様だが、入出庫予定の変更や追加項目自体の追加・削除など在庫データ自体の変更ではない場合は更新されない
 + create_user_name: `田村 太郎` (string) - 作成者
 + update_user_name: `田村 次郎` (string) - 更新者
 + user_group: `基本グループ` (string) - ユーザーグループ（最大255文字）