diff --git a/supar/models/const/crf/parser.py b/supar/models/const/crf/parser.py
index d1627657..4a57de5d 100644
--- a/supar/models/const/crf/parser.py
+++ b/supar/models/const/crf/parser.py
@@ -121,7 +121,7 @@ def pred_step(self, batch: Batch) -> Batch:
         batch.trees = [Tree.build(tree, [(i, j, self.CHART.vocab[label]) for i, j, label in chart])
                        for tree, chart in zip(trees, chart_preds)]
         if self.args.prob:
-            batch.probs = [prob[:i-1, 1:i].cpu() for i, prob in zip(lens, s_span)]
+            batch.probs = [prob[:i, 1:i+1].cpu() for i, prob in zip(lens, s_span)]
         return batch
 
     @classmethod