diff --git a/python/tvm/tir/buffer.py b/python/tvm/tir/buffer.py
index 726d5d1c988c..c2c158c77f78 100644
--- a/python/tvm/tir/buffer.py
+++ b/python/tvm/tir/buffer.py
@@ -179,7 +179,7 @@ def offset_of(self, indices):
 
     def __getitem__(self, indices):
         from ..arith import Analyzer  # pylint: disable=import-outside-toplevel
-        from .expr import BufferLoad, Ramp  # pylint: disable=import-outside-toplevel
+        from .expr import BufferLoad, Ramp, const  # pylint: disable=import-outside-toplevel
         from .stmt import BufferRegion  # pylint: disable=import-outside-toplevel
 
         if not isinstance(indices, (tuple, list)):
@@ -195,7 +195,11 @@ def __getitem__(self, indices):
                     stop = self.shape[i] if index.stop is None else index.stop
                     region.append(Range.from_min_extent(start, analyzer.simplify(stop - start)))
                 else:
-                    region.append(Range.from_min_extent(index, 1))
+                    region.append(
+                        Range.from_min_extent(
+                            index, const(1, index.dtype) if isinstance(index, PrimExpr) else 1
+                        )
+                    )
             return BufferRegion(self, region)
         else:
             expr_indices = []
diff --git a/tests/python/unittest/test_tvmscript_regression.py b/tests/python/unittest/test_tvmscript_regression.py
index d063c0fcab7f..44d3036596ba 100644
--- a/tests/python/unittest/test_tvmscript_regression.py
+++ b/tests/python/unittest/test_tvmscript_regression.py
@@ -17,6 +17,7 @@
 import numpy
 
 import tvm
+import tvm.testing
 from tvm.script import tir as T
 
 
@@ -73,9 +74,17 @@ def func_ref():
     tvm.ir.assert_structural_equal(test_case, func_ref)
 
 
+def test_tir_buffer_region_extent_correct_dtype():
+    @T.prim_func
+    def func(A: T.Buffer[(T.int64(16), T.int64(1)), "float32"]):
+        for i in T.grid(T.int64(16)):
+            with T.block("block"):
+                vi = T.axis.remap("S", [i])
+                T.reads(A[vi, T.int64(0) : T.int64(1)])
+                T.evaluate(0)
+
+    assert func.body.block.body.body.block.reads[0].region[0].extent.dtype == "int64"
+
+
 if __name__ == "__main__":
-    a = numpy.zeros((10, 10), dtype="int8")
-    test_multi_element_array_in_outmost_namespace()
-    test_different_dtype_assignment_to_var()
-    b = 1
-    test_var_capturing_order()
+    tvm.testing.main()