diff --git a/plugins/bc-blog/src/Model/Table/BlogPostsTable.php b/plugins/bc-blog/src/Model/Table/BlogPostsTable.php
index eaf9feb460..cd90551a29 100755
--- a/plugins/bc-blog/src/Model/Table/BlogPostsTable.php
+++ b/plugins/bc-blog/src/Model/Table/BlogPostsTable.php
@@ -28,7 +28,6 @@
 use Cake\Datasource\EntityInterface;
 use Cake\Event\EventInterface;
 use Cake\I18n\FrozenTime;
-use Cake\ORM\Exception\PersistenceFailedException;
 use Cake\ORM\Query;
 use Cake\Utility\Hash;
 use Cake\Validation\Validator;
@@ -675,8 +674,17 @@ public function copy($id = null, BlogPost $data = null)
         }
 
         $data->user_id = BcUtil::loginUser()['id'];
-        if ($data->name) $data->name .= '_copy';
-        $data->title .= '_copy';
+        if ($data->name) {
+            $baseName = $data->name;
+            $copySuffix = '_copy';
+            $data->name = mb_substr($baseName, 0, 255 - mb_strlen($copySuffix)) . $copySuffix;
+            for ($i = 1; $i <= 10 && $this->exists(['BlogPosts.name' => $data->name]); $i++) {
+                $suffix = '_' . $i;
+                $duplicateSuffix = $copySuffix . $suffix;
+                $data->name = mb_substr($baseName, 0, 255 - mb_strlen($duplicateSuffix)) . $duplicateSuffix;
+            }
+        }
+        $data->title = mb_substr($data->title, 0, 250) . '_copy';
         $data->no = $this->getMax('no', ['BlogPosts.blog_content_id' => $data->blog_content_id]) + 1;
         $data->status = false;
         $data->posted = \Cake\I18n\DateTime::now();
@@ -714,13 +722,6 @@ public function copy($id = null, BlogPost $data = null)
                 'oldData' => $oldData,
             ]);
             return $result;
-        } catch (PersistenceFailedException $e) {
-            if ($e->getEntity()->getError('name')) {
-                $data->eye_catch = $eyeCatch;
-                return $this->copy(null, $data);
-            } else {
-                return false;
-            }
         } catch (BcException $e) {
             throw $e;
         }
diff --git a/plugins/bc-blog/tests/TestCase/Model/BlogPostsTableTest.php b/plugins/bc-blog/tests/TestCase/Model/BlogPostsTableTest.php
index 50f389f61a..eabeed0cc0 100755
--- a/plugins/bc-blog/tests/TestCase/Model/BlogPostsTableTest.php
+++ b/plugins/bc-blog/tests/TestCase/Model/BlogPostsTableTest.php
@@ -636,6 +636,66 @@ public function testCopy()
         $this->assertFalse($result->status);
     }
 
+    /**
+     * コピーする（255文字境界で _copy を維持できる）
+     */
+    public function testCopyWithMaxLengthName()
+    {
+        $this->loadFixtureScenario(InitAppScenario::class);
+        $this->loginAdmin($this->getRequest());
+
+        $sourceName = str_repeat('a', 255);
+        $sourceTitle = str_repeat('b', 255);
+        BlogPostFactory::make([
+            'id' => 100,
+            'blog_content_id' => 6,
+            'no' => 100,
+            'name' => $sourceName,
+            'title' => $sourceTitle,
+            'status' => 1,
+        ])->persist();
+
+        $result = $this->BlogPostsTable->copy(100);
+
+        $this->assertEquals(255, mb_strlen($result->name));
+        $this->assertStringEndsWith('_copy', $result->name);
+        $this->assertEquals(255, mb_strlen($result->title));
+        $this->assertStringEndsWith('_copy', $result->title);
+    }
+
+    /**
+     * コピーする（重複時に _copy_1 を維持できる）
+     */
+    public function testCopyWithDuplicatedMaxLengthName()
+    {
+        $this->loadFixtureScenario(InitAppScenario::class);
+        $this->loginAdmin($this->getRequest());
+
+        $sourceName = str_repeat('a', 255);
+        $copiedName = mb_substr($sourceName, 0, 255 - mb_strlen('_copy')) . '_copy';
+        BlogPostFactory::make([
+            'id' => 101,
+            'blog_content_id' => 6,
+            'no' => 101,
+            'name' => $sourceName,
+            'title' => '元記事',
+            'status' => 1,
+        ])->persist();
+        BlogPostFactory::make([
+            'id' => 102,
+            'blog_content_id' => 6,
+            'no' => 102,
+            'name' => $copiedName,
+            'title' => '重複記事',
+            'status' => 1,
+        ])->persist();
+
+        $result = $this->BlogPostsTable->copy(101);
+
+        $this->assertEquals(255, mb_strlen($result->name));
+        $this->assertStringEndsWith('_copy_1', $result->name);
+    }
+
     /**
      * プレビュー用のデータを生成する
      */