diff --git a/mmcv/runner/epoch_based_runner.py b/mmcv/runner/epoch_based_runner.py
index 6d5a09462..aec827f3b 100644
--- a/mmcv/runner/epoch_based_runner.py
+++ b/mmcv/runner/epoch_based_runner.py
@@ -21,10 +21,10 @@ class EpochBasedRunner(BaseRunner):
         self.model.train()
         self.mode = 'train'
         self.data_loader = data_loader
-        self._max_iters = self._max_epochs * len(data_loader)
+        self._max_iters = self._max_epochs * len(self.data_loader)
         self.call_hook('before_train_epoch')
         time.sleep(2)  # Prevent possible deadlock during epoch transition
-        for i, data_batch in enumerate(data_loader):
+        for i, data_batch in enumerate(self.data_loader):
             self._inner_iter = i
             self.call_hook('before_train_iter')
             if self.batch_processor is None:
@@ -52,7 +52,7 @@ class EpochBasedRunner(BaseRunner):
         self.data_loader = data_loader
         self.call_hook('before_val_epoch')
         time.sleep(2)  # Prevent possible deadlock during epoch transition
-        for i, data_batch in enumerate(data_loader):
+        for i, data_batch in enumerate(self.data_loader):
             self._inner_iter = i
             self.call_hook('before_val_iter')
             with torch.no_grad():