diff --git a/planning/behavior_path_planner/include/behavior_path_planner/utils/avoidance/utils.hpp b/planning/behavior_path_planner/include/behavior_path_planner/utils/avoidance/utils.hpp
index c0bd621cc86b4..d012fd5f612fb 100644
--- a/planning/behavior_path_planner/include/behavior_path_planner/utils/avoidance/utils.hpp
+++ b/planning/behavior_path_planner/include/behavior_path_planner/utils/avoidance/utils.hpp
@@ -164,7 +164,7 @@ std::vector<ExtendedPredictedObject> getSafetyCheckTargetObjects(
 std::pair<PredictedObjects, PredictedObjects> separateObjectsByPath(
   const PathWithLaneId & path, const std::shared_ptr<const PlannerData> & planner_data,
   const AvoidancePlanningData & data, const std::shared_ptr<AvoidanceParameters> & parameters,
-  DebugData & debug);
+  const bool is_running, DebugData & debug);
 
 DrivableLanes generateExpandDrivableLanes(
   const lanelet::ConstLanelet & lanelet, const std::shared_ptr<const PlannerData> & planner_data,
diff --git a/planning/behavior_path_planner/src/scene_module/avoidance/avoidance_module.cpp b/planning/behavior_path_planner/src/scene_module/avoidance/avoidance_module.cpp
index 632aad8873906..8edc291fd560d 100644
--- a/planning/behavior_path_planner/src/scene_module/avoidance/avoidance_module.cpp
+++ b/planning/behavior_path_planner/src/scene_module/avoidance/avoidance_module.cpp
@@ -292,12 +292,16 @@ void AvoidanceModule::fillAvoidanceTargetObjects(
   using utils::avoidance::filterTargetObjects;
   using utils::avoidance::getTargetLanelets;
 
+  // Add margin in order to prevent avoidance request chattering only when the module is running.
+  const auto is_running = getCurrentStatus() == ModuleStatus::RUNNING ||
+                          getCurrentStatus() == ModuleStatus::WAITING_APPROVAL;
+
   // Separate dynamic objects based on whether they are inside or outside of the expanded lanelets.
   const auto [object_within_target_lane, object_outside_target_lane] =
     utils::avoidance::separateObjectsByPath(
       utils::resamplePathWithSpline(
         helper_.getPreviousSplineShiftPath().path, parameters_->resample_interval_for_output),
-      planner_data_, data, parameters_, debug);
+      planner_data_, data, parameters_, is_running, debug);
 
   for (const auto & object : object_outside_target_lane.objects) {
     ObjectData other_object;
diff --git a/planning/behavior_path_planner/src/utils/avoidance/utils.cpp b/planning/behavior_path_planner/src/utils/avoidance/utils.cpp
index 0e7eb87feed9b..ed2e42bf0c5ff 100644
--- a/planning/behavior_path_planner/src/utils/avoidance/utils.cpp
+++ b/planning/behavior_path_planner/src/utils/avoidance/utils.cpp
@@ -29,9 +29,12 @@
 
 #include <tier4_planning_msgs/msg/avoidance_debug_factor.hpp>
 
+#include <boost/geometry.hpp>
 #include <boost/geometry/algorithms/convex_hull.hpp>
 #include <boost/geometry/algorithms/correct.hpp>
 #include <boost/geometry/algorithms/union.hpp>
+#include <boost/geometry/geometries/geometries.hpp>
+#include <boost/geometry/geometries/point_xy.hpp>
 #include <boost/geometry/strategies/convex_hull.hpp>
 
 #include <lanelet2_routing/RoutingGraphContainer.h>
@@ -1602,7 +1605,7 @@ std::vector<ExtendedPredictedObject> getSafetyCheckTargetObjects(
 std::pair<PredictedObjects, PredictedObjects> separateObjectsByPath(
   const PathWithLaneId & path, const std::shared_ptr<const PlannerData> & planner_data,
   const AvoidancePlanningData & data, const std::shared_ptr<AvoidanceParameters> & parameters,
-  DebugData & debug)
+  const bool is_running, DebugData & debug)
 {
   PredictedObjects target_objects;
   PredictedObjects other_objects;
@@ -1639,6 +1642,25 @@ std::pair<PredictedObjects, PredictedObjects> separateObjectsByPath(
     }
   }
 
+  // expand detection area width only when the module is running.
+  if (is_running) {
+    constexpr int PER_CIRCLE = 36;
+    constexpr double MARGIN = 1.0;  // [m]
+    boost::geometry::strategy::buffer::distance_symmetric<double> distance_strategy(MARGIN);
+    boost::geometry::strategy::buffer::join_round join_strategy(PER_CIRCLE);
+    boost::geometry::strategy::buffer::end_round end_strategy(PER_CIRCLE);
+    boost::geometry::strategy::buffer::point_circle circle_strategy(PER_CIRCLE);
+    boost::geometry::strategy::buffer::side_straight side_strategy;
+    boost::geometry::model::multi_polygon<Polygon2d> result;
+    // Create the buffer of a multi polygon
+    boost::geometry::buffer(
+      attention_area, result, distance_strategy, side_strategy, join_strategy, end_strategy,
+      circle_strategy);
+    if (!result.empty()) {
+      attention_area = result.front();
+    }
+  }
+
   debug.detection_area = toMsg(attention_area, data.reference_pose.position.z);
 
   const auto objects = planner_data->dynamic_object->objects;