diff --git a/src/lib/client.ts b/src/lib/client.ts
index 2db59f2..0780bcc 100644
--- a/src/lib/client.ts
+++ b/src/lib/client.ts
@@ -17,22 +17,39 @@ export const createUeuse = async (data: ApiMap["ueuse/create"]["body"], title: s
   const mem = Memory.memory;
   const maxLength = mem.max_length;
   const excessedMessage = "👉返信に続きがあります。";
-
-  let remainingText = data.text;
+  
+  // 行単位で分割
+  let lines = data.text.split(EOL);
   let firstUniqid = "";
 
-  while (remainingText.length > 0) {
+  while (lines.length > 0) {
     let currentText = "";
-    let bodyTextLength = 0;
+    
+    const limit = maxLength - (excessedMessage.length + EOL.length * 2);
 
-    if (remainingText.length <= maxLength) {
-      currentText = remainingText;
-      bodyTextLength = remainingText.length;
-      remainingText = "";
-    } else {
-      bodyTextLength = maxLength - excessedMessage.length - 2;
-      currentText = remainingText.slice(0, bodyTextLength) + EOL.repeat(2) + excessedMessage;
-      remainingText = remainingText.slice(bodyTextLength);
+    while (lines.length > 0) {
+      const nextLine = lines[0];
+      if (nextLine === undefined) break;
+
+      if (nextLine.length > limit && currentText === "") {
+        const targetLine = lines.shift() || "";
+        currentText = targetLine.slice(0, limit);
+
+        lines.unshift(targetLine.slice(limit));
+        break;
+      }
+
+      const potentialText = currentText ? currentText + EOL + nextLine : nextLine;
+      if (potentialText.length <= limit) {
+        currentText = potentialText;
+        lines.shift();
+      } else {
+        break;
+      }
+    }
+
+    if (lines.length > 0) {
+      currentText += EOL.repeat(2) + excessedMessage;
     }
 
     let postedUniqid = "";
@@ -64,10 +81,7 @@ export const createUeuse = async (data: ApiMap["ueuse/create"]["body"], title: s
       break;
     }
 
-    if (firstUniqid === "") {
-      firstUniqid = postedUniqid;
-    }
-
+    if (firstUniqid === "") firstUniqid = postedUniqid;
     console.log(`${title}を投稿:`, postedUniqid);
   }
-}
+}
\ No newline at end of file