diff --git a/black.py b/black.py
index c1cc08021f3..9a01b62cc46 100644
--- a/black.py
+++ b/black.py
@@ -1289,7 +1289,7 @@ def __str__(self) -> str:
         if not self:
             return "\n"
 
-        indent = "    " * self.depth
+        indent = "\t" * self.depth
         leaves = iter(self.leaves)
         first = next(leaves)
         res = f"{first.prefix}{indent}{first.value}"