diff --git a/maskrcnn_benchmark/structures/bounding_box.py b/maskrcnn_benchmark/structures/bounding_box.py
index 25791d578..bb17cad8b 100644
--- a/maskrcnn_benchmark/structures/bounding_box.py
+++ b/maskrcnn_benchmark/structures/bounding_box.py
@@ -61,12 +61,12 @@ def convert(self, mode):
         # self.mode
         xmin, ymin, xmax, ymax = self._split_into_xyxy()
         if mode == "xyxy":
-            bbox = torch.cat((xmin, ymin, xmax, ymax), dim=-1)
+            bbox = torch.cat((xmin, ymin, xmax, ymax), dim=1)
             bbox = BoxList(bbox, self.size, mode=mode)
         else:
             TO_REMOVE = 1
             bbox = torch.cat(
-                (xmin, ymin, xmax - xmin + TO_REMOVE, ymax - ymin + TO_REMOVE), dim=-1
+                (xmin, ymin, xmax - xmin + TO_REMOVE, ymax - ymin + TO_REMOVE), dim=1
             )
             bbox = BoxList(bbox, self.size, mode=mode)
         bbox._copy_extra_fields(self)
@@ -74,11 +74,11 @@ def convert(self, mode):
 
     def _split_into_xyxy(self):
         if self.mode == "xyxy":
-            xmin, ymin, xmax, ymax = self.bbox.split(1, dim=-1)
+            xmin, ymin, xmax, ymax = self.bbox.split(1, dim=1)
             return xmin, ymin, xmax, ymax
         elif self.mode == "xywh":
             TO_REMOVE = 1
-            xmin, ymin, w, h = self.bbox.split(1, dim=-1)
+            xmin, ymin, w, h = self.bbox.split(1, dim=1)
             return (
                 xmin,
                 ymin,
@@ -115,7 +115,7 @@ def resize(self, size, *args, **kwargs):
         scaled_ymin = ymin * ratio_height
         scaled_ymax = ymax * ratio_height
         scaled_box = torch.cat(
-            (scaled_xmin, scaled_ymin, scaled_xmax, scaled_ymax), dim=-1
+            (scaled_xmin, scaled_ymin, scaled_xmax, scaled_ymax), dim=1
         )
         bbox = BoxList(scaled_box, size, mode="xyxy")
         # bbox._copy_extra_fields(self)
@@ -154,7 +154,7 @@ def transpose(self, method):
             transposed_ymax = image_height - ymin
 
         transposed_boxes = torch.cat(
-            (transposed_xmin, transposed_ymin, transposed_xmax, transposed_ymax), dim=-1
+            (transposed_xmin, transposed_ymin, transposed_xmax, transposed_ymax), dim=1
         )
         bbox = BoxList(transposed_boxes, self.size, mode="xyxy")
         # bbox._copy_extra_fields(self)
@@ -182,7 +182,7 @@ def crop(self, box):
             is_empty = (cropped_xmin == cropped_xmax) | (cropped_ymin == cropped_ymax)
 
         cropped_box = torch.cat(
-            (cropped_xmin, cropped_ymin, cropped_xmax, cropped_ymax), dim=-1
+            (cropped_xmin, cropped_ymin, cropped_xmax, cropped_ymax), dim=1
         )
         bbox = BoxList(cropped_box, (w, h), mode="xyxy")
         # bbox._copy_extra_fields(self)