diff --git a/planning/autoware_path_generator/src/utils.cpp b/planning/autoware_path_generator/src/utils.cpp
index ee3881d8a..ec6df4621 100644
--- a/planning/autoware_path_generator/src/utils.cpp
+++ b/planning/autoware_path_generator/src/utils.cpp
@@ -539,7 +539,7 @@ lanelet::ConstLanelets extract_lanelets_from_path(
     const auto & path_point = refined_path.points.at(i);
     int64_t lane_id = path_point.lane_ids.at(0);
     lanelet::ConstLanelet lanelet = planner_data->lanelet_map_ptr->laneletLayer.get(lane_id);
-    bool is_unique =
+    const bool is_unique =
       std::find(refined_path_lanelets.begin(), refined_path_lanelets.end(), lanelet) ==
       refined_path_lanelets.end();
     if (is_unique) {