diff --git a/django/core/db/backends/sqlite3.py b/django/core/db/backends/sqlite3.py
index 9599b79b7d..0137661914 100644
--- a/django/core/db/backends/sqlite3.py
+++ b/django/core/db/backends/sqlite3.py
@@ -56,7 +56,7 @@ class FormatStylePlaceholderCursor(Database.Cursor):
         return Database.Cursor.execute(self, query, params)
         
     def executemany(self, query, params=[]):
-        query = self.convert_query(query, len(params))
+        query = self.convert_query(query, len(params[0]))
         return Database.Cursor.executemany(self, query, params)
         
     def convert_query(self, query, num_params):