diff --git a/perception/detection_by_tracker/include/detection_by_tracker/detection_by_tracker_core.hpp b/perception/detection_by_tracker/include/detection_by_tracker/detection_by_tracker_core.hpp
index 10affd0b94ffd..771747c80bb95 100644
--- a/perception/detection_by_tracker/include/detection_by_tracker/detection_by_tracker_core.hpp
+++ b/perception/detection_by_tracker/include/detection_by_tracker/detection_by_tracker_core.hpp
@@ -16,6 +16,7 @@
 #define DETECTION_BY_TRACKER__DETECTION_BY_TRACKER_CORE_HPP_
 
 #include "detection_by_tracker/debugger.hpp"
+#include "detection_by_tracker/utils.hpp"
 
 #include <euclidean_cluster/euclidean_cluster.hpp>
 #include <euclidean_cluster/utils.hpp>
@@ -39,8 +40,6 @@
 #include <tf2_geometry_msgs/tf2_geometry_msgs.hpp>
 #endif
 
-#include "utils/utils.hpp"
-
 #include <tf2_ros/buffer.h>
 #include <tf2_ros/transform_listener.h>
 
@@ -82,7 +81,7 @@ class DetectionByTracker : public rclcpp::Node
   std::map<uint8_t, int> max_search_distance_for_merger_;
   std::map<uint8_t, int> max_search_distance_for_divider_;
 
-  utils::TrackerIgnoreLabel tracker_ignore_;
+  detection_by_tracker::utils::TrackerIgnoreLabel tracker_ignore_;
 
   void setMaxSearchRange();
 
diff --git a/perception/detection_by_tracker/include/utils/utils.hpp b/perception/detection_by_tracker/include/detection_by_tracker/utils.hpp
similarity index 81%
rename from perception/detection_by_tracker/include/utils/utils.hpp
rename to perception/detection_by_tracker/include/detection_by_tracker/utils.hpp
index 3f39125b95e03..ed783b0343a14 100644
--- a/perception/detection_by_tracker/include/utils/utils.hpp
+++ b/perception/detection_by_tracker/include/detection_by_tracker/utils.hpp
@@ -12,11 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#ifndef UTILS__UTILS_HPP_
-#define UTILS__UTILS_HPP_
+#ifndef DETECTION_BY_TRACKER__UTILS_HPP_
+#define DETECTION_BY_TRACKER__UTILS_HPP_
 
 #include <cstdint>
 
+namespace detection_by_tracker
+{
 namespace utils
 {
 struct TrackerIgnoreLabel
@@ -32,5 +34,6 @@ struct TrackerIgnoreLabel
   bool isIgnore(const uint8_t label) const;
 };  // struct TrackerIgnoreLabel
 }  // namespace utils
+}  // namespace detection_by_tracker
 
-#endif  // UTILS__UTILS_HPP_
+#endif  // DETECTION_BY_TRACKER__UTILS_HPP_
diff --git a/perception/detection_by_tracker/src/utils.cpp b/perception/detection_by_tracker/src/utils.cpp
index 29a500a24cf32..b2655d99abacc 100644
--- a/perception/detection_by_tracker/src/utils.cpp
+++ b/perception/detection_by_tracker/src/utils.cpp
@@ -12,10 +12,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#include "utils/utils.hpp"
+#include "detection_by_tracker/utils.hpp"
 
 #include <autoware_auto_perception_msgs/msg/object_classification.hpp>
 
+namespace detection_by_tracker
+{
 namespace utils
 {
 using Label = autoware_auto_perception_msgs::msg::ObjectClassification;
@@ -28,3 +30,4 @@ bool TrackerIgnoreLabel::isIgnore(const uint8_t label) const
          (label == Label::BICYCLE && BICYCLE) || (label == Label::PEDESTRIAN && PEDESTRIAN);
 }
 }  // namespace utils
+}  // namespace detection_by_tracker