diff --git a/train_ssd.py b/train_ssd.py
index a6c09a8..5111144 100644
--- a/train_ssd.py
+++ b/train_ssd.py
@@ -105,7 +105,7 @@
 # checkpoint related configuration
 tf.app.flags.DEFINE_string(
     'checkpoint_path', './model',
-    'The path to a checkpoint from which to fine-tune.')
+    'The path to a checkpoint from which to fine-tune. If it is None, training model from scratch.')
 tf.app.flags.DEFINE_string(
     'checkpoint_model_scope', 'vgg_16',
     'Model scope in the checkpoint. None if the same as the trained model.')
diff --git a/utility/scaffolds.py b/utility/scaffolds.py
index 820dabb..13ac082 100644
--- a/utility/scaffolds.py
+++ b/utility/scaffolds.py
@@ -25,6 +25,9 @@ def get_init_fn_for_scaffold(model_dir, checkpoint_path, model_scope, checkpoint
     if tf.train.latest_checkpoint(model_dir):
         tf.logging.info('Ignoring --checkpoint_path because a checkpoint already exists in %s.' % model_dir)
         return None
+    if checkpoint_path is None:
+        tf.logging.info('Training detector from scratch.')
+        return None
     exclusion_scopes = []
     if checkpoint_exclude_scopes:
         exclusion_scopes = [scope.strip() for scope in checkpoint_exclude_scopes.split(',')]