diff --git a/src/api/endpoints/posts/create.js b/src/api/endpoints/posts/create.js
index 3a527023c1..dc73725a7f 100644
--- a/src/api/endpoints/posts/create.js
+++ b/src/api/endpoints/posts/create.js
@@ -18,7 +18,7 @@ import config from '../../../conf';
 /**
  * 最大文字数
  */
-const maxTextLength = 500;
+const maxTextLength = 1000;
 
 /**
  * 添付できるファイルの数
diff --git a/src/web/app/desktop/tags/post-form.tag b/src/web/app/desktop/tags/post-form.tag
index cc9764e6f6..872e928816 100644
--- a/src/web/app/desktop/tags/post-form.tag
+++ b/src/web/app/desktop/tags/post-form.tag
@@ -13,7 +13,7 @@
 	<button ref="upload" title="PCからファイルを添付" onclick={ selectFile }><i class="fa fa-upload"></i></button>
 	<button ref="drive" title="ドライブからファイルを添付" onclick={ selectFileFromDrive }><i class="fa fa-cloud"></i></button>
 	<button class="cat" title="Insert The Cat" onclick={ cat }><i class="fa fa-smile-o"></i></button>
-	<p class="text-count { over: refs.text.value.length > 500 }">のこり{ 500 - refs.text.value.length }文字</p>
+	<p class="text-count { over: refs.text.value.length > 1000 }">のこり{ 1000 - refs.text.value.length }文字</p>
 	<button class={ wait: wait } ref="submit" disabled={ wait || (refs.text.value.length == 0 && files.length == 0) } onclick={ post }>{ wait ? '投稿中' : opts.reply ? '返信' : '投稿' }
 		<mk-ellipsis if={ wait }></mk-ellipsis>
 	</button>
diff --git a/src/web/app/mobile/tags/post-form.tag b/src/web/app/mobile/tags/post-form.tag
index 312046363c..900f742e85 100644
--- a/src/web/app/mobile/tags/post-form.tag
+++ b/src/web/app/mobile/tags/post-form.tag
@@ -2,7 +2,7 @@
 	<header>
 		<div>
 			<button class="cancel" onclick={ cancel }><i class="fa fa-times"></i></button>
-			<div><span class="text-count { over: refs.text.value.length > 500 }">{ 500 - refs.text.value.length }</span>
+			<div><span class="text-count { over: refs.text.value.length > 1000 }">{ 1000 - refs.text.value.length }</span>
 				<button class="submit" onclick={ post }>投稿</button>
 			</div>
 		</div>