diff --git a/common/object_recognition_utils/include/object_recognition_utils/conversion.hpp b/common/object_recognition_utils/include/object_recognition_utils/conversion.hpp
index 6d07d161bf069..207f76a1c31a8 100644
--- a/common/object_recognition_utils/include/object_recognition_utils/conversion.hpp
+++ b/common/object_recognition_utils/include/object_recognition_utils/conversion.hpp
@@ -28,7 +28,6 @@ using autoware_perception_msgs::msg::TrackedObjects;
 DetectedObject toDetectedObject(const TrackedObject & tracked_object);
 DetectedObjects toDetectedObjects(const TrackedObjects & tracked_objects);
 TrackedObject toTrackedObject(const DetectedObject & detected_object);
-TrackedObjects toTrackedObjects(const DetectedObjects & detected_objects);
 }  // namespace object_recognition_utils
 
 #endif  // OBJECT_RECOGNITION_UTILS__CONVERSION_HPP_
diff --git a/common/object_recognition_utils/src/conversion.cpp b/common/object_recognition_utils/src/conversion.cpp
index ac65b35c6809a..c9c057ad93644 100644
--- a/common/object_recognition_utils/src/conversion.cpp
+++ b/common/object_recognition_utils/src/conversion.cpp
@@ -68,15 +68,4 @@ TrackedObject toTrackedObject(const DetectedObject & detected_object)
   tracked_object.shape = detected_object.shape;
   return tracked_object;
 }
-
-TrackedObjects toTrackedObjects(const DetectedObjects & detected_objects)
-{
-  TrackedObjects tracked_objects;
-  tracked_objects.header = detected_objects.header;
-
-  for (const auto & detected_object : detected_objects.objects) {
-    tracked_objects.objects.push_back(toTrackedObject(detected_object));
-  }
-  return tracked_objects;
-}
 }  // namespace object_recognition_utils