diff --git a/CHANGELOG.md b/CHANGELOG.md
index 30e2e57b7d..ea34fa9ef7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,11 @@
 
 -->
 
+## 202x.x.x (Unreleased)
+
+### Client
+- Enhance: ハッシュタグ入力時に、本文の末尾の行に何も書かれていない場合は新たにスペースを追加しないように
+
 ## 2023.12.2
 
 ### General
diff --git a/packages/frontend/src/components/MkPostForm.vue b/packages/frontend/src/components/MkPostForm.vue
index 3aacf4c2da..b86f50eac6 100644
--- a/packages/frontend/src/components/MkPostForm.vue
+++ b/packages/frontend/src/components/MkPostForm.vue
@@ -752,7 +752,17 @@ async function post(ev?: MouseEvent) {
 
 	if (withHashtags.value && hashtags.value && hashtags.value.trim() !== '') {
 		const hashtags_ = hashtags.value.trim().split(' ').map(x => x.startsWith('#') ? x : '#' + x).join(' ');
-		postData.text = postData.text ? `${postData.text} ${hashtags_}` : hashtags_;
+		if (!postData.text) {
+			postData.text = hashtags_;
+		} else {
+			const postTextLines = postData.text.split('\n');
+			if (postTextLines[postTextLines.length - 1].trim() === '') {
+				postTextLines[postTextLines.length - 1] += hashtags_;
+			} else {
+				postTextLines[postTextLines.length - 1] += ' ' + hashtags_;
+			}
+			postData.text = postTextLines.join('\n');
+		}
 	}
 
 	// plugin