diff --git a/launch/tier4_perception_launch/launch/obstacle_segmentation/ground_segmentation/ground_segmentation.launch.py b/launch/tier4_perception_launch/launch/obstacle_segmentation/ground_segmentation/ground_segmentation.launch.py
index b21a7c082407d..f502aef017979 100644
--- a/launch/tier4_perception_launch/launch/obstacle_segmentation/ground_segmentation/ground_segmentation.launch.py
+++ b/launch/tier4_perception_launch/launch/obstacle_segmentation/ground_segmentation/ground_segmentation.launch.py
@@ -78,7 +78,7 @@ def create_additional_pipeline(self, lidar_name):
         )
         min_z = (
             self.vehicle_info["min_height_offset"]
-            - self.ground_segmentation_param[f"{lidar_name}_crop_box_filter"]["parameters"][
+            + self.ground_segmentation_param[f"{lidar_name}_crop_box_filter"]["parameters"][
                 "margin_min_z"
             ]
         )
@@ -226,7 +226,7 @@ def create_common_pipeline(self, input_topic, output_topic):
         )
         min_z = (
             self.vehicle_info["min_height_offset"]
-            - self.ground_segmentation_param["common_crop_box_filter"]["parameters"]["margin_min_z"]
+            + self.ground_segmentation_param["common_crop_box_filter"]["parameters"]["margin_min_z"]
         )
         components = []
         components.append(