diff --git a/perception/autoware_probabilistic_occupancy_grid_map/include/autoware/probabilistic_occupancy_grid_map/utils/utils.hpp b/perception/autoware_probabilistic_occupancy_grid_map/include/autoware/probabilistic_occupancy_grid_map/utils/utils.hpp
index a8288d2720f48..41c7294ded849 100644
--- a/perception/autoware_probabilistic_occupancy_grid_map/include/autoware/probabilistic_occupancy_grid_map/utils/utils.hpp
+++ b/perception/autoware_probabilistic_occupancy_grid_map/include/autoware/probabilistic_occupancy_grid_map/utils/utils.hpp
@@ -120,8 +120,6 @@ bool extractCommonPointCloud(
   const sensor_msgs::msg::PointCloud2 & obstacle_pc, const sensor_msgs::msg::PointCloud2 & raw_pc,
   sensor_msgs::msg::PointCloud2 & output_obstacle_pc);
 
-unsigned char getApproximateOccupancyState(const unsigned char & value);
-
 }  // namespace utils
 }  // namespace autoware::occupancy_grid_map
 
diff --git a/perception/autoware_probabilistic_occupancy_grid_map/lib/utils/utils.cpp b/perception/autoware_probabilistic_occupancy_grid_map/lib/utils/utils.cpp
index 902de2148cffe..9d190664b8858 100644
--- a/perception/autoware_probabilistic_occupancy_grid_map/lib/utils/utils.cpp
+++ b/perception/autoware_probabilistic_occupancy_grid_map/lib/utils/utils.cpp
@@ -191,21 +191,5 @@ bool extractCommonPointCloud(
   return true;
 }
 
-/**
- * @brief Convert unsigned char value to closest cost value
- * @param cost Cost value
- * @return Probability
- */
-unsigned char getApproximateOccupancyState(const unsigned char & value)
-{
-  if (value >= cost_value::OCCUPIED_THRESHOLD) {
-    return cost_value::LETHAL_OBSTACLE;
-  } else if (value <= cost_value::FREE_THRESHOLD) {
-    return cost_value::FREE_SPACE;
-  } else {
-    return cost_value::NO_INFORMATION;
-  }
-}
-
 }  // namespace utils
 }  // namespace autoware::occupancy_grid_map
diff --git a/perception/autoware_probabilistic_occupancy_grid_map/src/fusion/synchronized_grid_map_fusion_node.cpp b/perception/autoware_probabilistic_occupancy_grid_map/src/fusion/synchronized_grid_map_fusion_node.cpp
index 0a78b10055dd0..28a5759eeb7b0 100644
--- a/perception/autoware_probabilistic_occupancy_grid_map/src/fusion/synchronized_grid_map_fusion_node.cpp
+++ b/perception/autoware_probabilistic_occupancy_grid_map/src/fusion/synchronized_grid_map_fusion_node.cpp
@@ -369,42 +369,6 @@ OccupancyGridMapFixedBlindSpot GridMapFusionNode::SingleFrameOccupancyFusion(
   return fused_map;
 }
 
-/**
- * @brief Update occupancy grid map with asynchronous input (currently unused)
- *
- * @param occupancy_grid_msg
- */
-void GridMapFusionNode::updateGridMap(
-  const nav_msgs::msg::OccupancyGrid::ConstSharedPtr & occupancy_grid_msg)
-{
-  // get updater map origin
-
-  // origin is set to current updater map
-  auto map_for_update = OccupancyGridMsgToCostmap2D(*occupancy_grid_msg);
-
-  // update
-  occupancy_grid_map_updater_ptr_->update(map_for_update);
-}
-
-nav2_costmap_2d::Costmap2D GridMapFusionNode::OccupancyGridMsgToCostmap2D(
-  const nav_msgs::msg::OccupancyGrid & occupancy_grid_map)
-{
-  nav2_costmap_2d::Costmap2D costmap2d(
-    occupancy_grid_map.info.width, occupancy_grid_map.info.height,
-    occupancy_grid_map.info.resolution, occupancy_grid_map.info.origin.position.x,
-    occupancy_grid_map.info.origin.position.y, 0);
-
-  for (unsigned int i = 0; i < occupancy_grid_map.info.width; i++) {
-    for (unsigned int j = 0; j < occupancy_grid_map.info.height; j++) {
-      const unsigned int index = i + j * occupancy_grid_map.info.width;
-      costmap2d.setCost(
-        i, j, cost_value::inverse_cost_translation_table[occupancy_grid_map.data[index]]);
-    }
-  }
-
-  return costmap2d;
-}
-
 OccupancyGridMapFixedBlindSpot GridMapFusionNode::OccupancyGridMsgToGridMap(
   const nav_msgs::msg::OccupancyGrid & occupancy_grid_map)
 {
diff --git a/perception/autoware_probabilistic_occupancy_grid_map/src/fusion/synchronized_grid_map_fusion_node.hpp b/perception/autoware_probabilistic_occupancy_grid_map/src/fusion/synchronized_grid_map_fusion_node.hpp
index 691575299a8c7..23aeb76826e5f 100644
--- a/perception/autoware_probabilistic_occupancy_grid_map/src/fusion/synchronized_grid_map_fusion_node.hpp
+++ b/perception/autoware_probabilistic_occupancy_grid_map/src/fusion/synchronized_grid_map_fusion_node.hpp
@@ -66,16 +66,12 @@ class GridMapFusionNode : public rclcpp::Node
     const std::string & frame_id, const builtin_interfaces::msg::Time & stamp,
     const float & robot_pose_z, const nav2_costmap_2d::Costmap2D & occupancy_grid_map);
 
-  nav2_costmap_2d::Costmap2D OccupancyGridMsgToCostmap2D(
-    const nav_msgs::msg::OccupancyGrid & occupancy_grid_map);
   OccupancyGridMapFixedBlindSpot OccupancyGridMsgToGridMap(
     const nav_msgs::msg::OccupancyGrid & occupancy_grid_map);
   OccupancyGridMapFixedBlindSpot SingleFrameOccupancyFusion(
     std::vector<OccupancyGridMapFixedBlindSpot> & occupancy_grid_maps,
     const builtin_interfaces::msg::Time latest_stamp, const std::vector<double> & weights);
 
-  void updateGridMap(const nav_msgs::msg::OccupancyGrid::ConstSharedPtr & occupancy_grid_msg);
-
   void setPeriod(const int64_t new_period);
   void timer_callback();
   void publish();