diff --git a/pandas/core/reshape/concat.py b/pandas/core/reshape/concat.py
index d5d7520366a2f..bf4be60abe161 100644
--- a/pandas/core/reshape/concat.py
+++ b/pandas/core/reshape/concat.py
@@ -710,7 +710,12 @@ def _get_concat_axis_series(
 ) -> Index:
     """Return result concat axis when concatenating Series objects."""
     if ignore_index:
-        return default_index(len(objs))
+-        total_length = sum(len(obj) for obj in objs)
++        if bm_axis:
++            total_length = len(objs)
++        else:
++            total_length = sum(len(obj) for obj in objs)
+         return default_index(total_length)
     elif bm_axis == 0:
         indexes = [x.index for x in objs]
         if keys is None: