diff --git a/evaluator/perception_online_evaluator/README.md b/evaluator/perception_online_evaluator/README.md
index 7df375ac236d0..17e7e1a2b5652 100644
--- a/evaluator/perception_online_evaluator/README.md
+++ b/evaluator/perception_online_evaluator/README.md
@@ -155,11 +155,11 @@ where:
 
 ## Inputs / Outputs
 
-| Name              | Type                                              | Description                                       |
-| ----------------- | ------------------------------------------------- | ------------------------------------------------- |
-| `~/input/objects` | `autoware_perception_msgs::msg::PredictedObjects` | The predicted objects to evaluate.                |
-| `~/metrics`       | `diagnostic_msgs::msg::DiagnosticArray`           | Diagnostic information about perception accuracy. |
-| `~/markers`       | `visualization_msgs::msg::MarkerArray`            | Visual markers for debugging and visualization.   |
+| Name              | Type                                              | Description                                     |
+| ----------------- | ------------------------------------------------- | ----------------------------------------------- |
+| `~/input/objects` | `autoware_perception_msgs::msg::PredictedObjects` | The predicted objects to evaluate.              |
+| `~/metrics`       | `tier4_metric_msgs::msg::MetricArray`             | Metric information about perception accuracy.   |
+| `~/markers`       | `visualization_msgs::msg::MarkerArray`            | Visual markers for debugging and visualization. |
 
 ## Parameters
 
diff --git a/evaluator/perception_online_evaluator/include/perception_online_evaluator/perception_online_evaluator_node.hpp b/evaluator/perception_online_evaluator/include/perception_online_evaluator/perception_online_evaluator_node.hpp
index ea560a48f928b..61c1ba40134df 100644
--- a/evaluator/perception_online_evaluator/include/perception_online_evaluator/perception_online_evaluator_node.hpp
+++ b/evaluator/perception_online_evaluator/include/perception_online_evaluator/perception_online_evaluator_node.hpp
@@ -23,9 +23,10 @@
 #include "tf2_ros/transform_listener.h"
 
 #include "autoware_perception_msgs/msg/predicted_objects.hpp"
-#include "diagnostic_msgs/msg/diagnostic_array.hpp"
 #include "nav_msgs/msg/odometry.hpp"
 #include "visualization_msgs/msg/marker_array.hpp"
+#include <tier4_metric_msgs/msg/metric.hpp>
+#include <tier4_metric_msgs/msg/metric_array.hpp>
 
 #include <array>
 #include <deque>
@@ -38,8 +39,6 @@ namespace perception_diagnostics
 using autoware::universe_utils::Accumulator;
 using autoware_perception_msgs::msg::ObjectClassification;
 using autoware_perception_msgs::msg::PredictedObjects;
-using diagnostic_msgs::msg::DiagnosticArray;
-using diagnostic_msgs::msg::DiagnosticStatus;
 using nav_msgs::msg::Odometry;
 using TFMessage = tf2_msgs::msg::TFMessage;
 
@@ -60,15 +59,34 @@ class PerceptionOnlineEvaluatorNode : public rclcpp::Node
    */
   void onObjects(const PredictedObjects::ConstSharedPtr objects_msg);
 
-  DiagnosticStatus generateDiagnosticStatus(
-    const std::string metric, const Accumulator<double> & metric_stat) const;
-  DiagnosticStatus generateDiagnosticStatus(
-    const std::string & metric, const double metric_value) const;
+  /**
+   * @brief Convert metric statistic to `tier4_metric_msgs::msg::Metric` and append to
+   * `tier4_metric_msgs::msg::MetricArray`.
+   *
+   * @param metric Metric name.
+   * @param metric_stat Metric statistic.
+   * @param metrics_msg Metrics value container.
+   */
+  void toMetricMsg(
+    const std::string & metric, const Accumulator<double> & metric_stat,
+    tier4_metric_msgs::msg::MetricArray & metrics_msg) const;
+
+  /**
+   * @brief Convert metric value to `tier4_metric_msgs::msg::Metric` and append to
+   * `tier4_metric_msgs::msg::MetricArray
+   *
+   * @param metric Metric name.
+   * @param metric_stat Metric value.
+   * @param metrics_msg Metrics value container.
+   */
+  void toMetricMsg(
+    const std::string & metric, const double metric_value,
+    tier4_metric_msgs::msg::MetricArray & metrics_msg) const;
 
 private:
   // Subscribers and publishers
   rclcpp::Subscription<PredictedObjects>::SharedPtr objects_sub_;
-  rclcpp::Publisher<DiagnosticArray>::SharedPtr metrics_pub_;
+  rclcpp::Publisher<tier4_metric_msgs::msg::MetricArray>::SharedPtr metrics_pub_;
   rclcpp::Publisher<MarkerArray>::SharedPtr pub_marker_;
 
   // TF
diff --git a/evaluator/perception_online_evaluator/package.xml b/evaluator/perception_online_evaluator/package.xml
index 654586a76453d..1e7c0a7d128e6 100644
--- a/evaluator/perception_online_evaluator/package.xml
+++ b/evaluator/perception_online_evaluator/package.xml
@@ -23,7 +23,6 @@
   <depend>autoware_perception_msgs</depend>
   <depend>autoware_universe_utils</depend>
   <depend>autoware_vehicle_info_utils</depend>
-  <depend>diagnostic_msgs</depend>
   <depend>eigen</depend>
   <depend>geometry_msgs</depend>
   <depend>glog</depend>
@@ -33,6 +32,7 @@
   <depend>rclcpp_components</depend>
   <depend>tf2</depend>
   <depend>tf2_ros</depend>
+  <depend>tier4_metric_msgs</depend>
 
   <test_depend>ament_cmake_ros</test_depend>
   <test_depend>ament_index_cpp</test_depend>
diff --git a/evaluator/perception_online_evaluator/src/perception_online_evaluator_node.cpp b/evaluator/perception_online_evaluator/src/perception_online_evaluator_node.cpp
index abbdbd382498a..7d8344c24819c 100644
--- a/evaluator/perception_online_evaluator/src/perception_online_evaluator_node.cpp
+++ b/evaluator/perception_online_evaluator/src/perception_online_evaluator_node.cpp
@@ -50,7 +50,7 @@ PerceptionOnlineEvaluatorNode::PerceptionOnlineEvaluatorNode(
 
   objects_sub_ = create_subscription<PredictedObjects>(
     "~/input/objects", 1, std::bind(&PerceptionOnlineEvaluatorNode::onObjects, this, _1));
-  metrics_pub_ = create_publisher<DiagnosticArray>("~/metrics", 1);
+  metrics_pub_ = create_publisher<tier4_metric_msgs::msg::MetricArray>("~/metrics", 1);
   pub_marker_ = create_publisher<MarkerArray>("~/markers", 10);
 
   tf_buffer_ = std::make_unique<tf2_ros::Buffer>(this->get_clock());
@@ -65,7 +65,8 @@ PerceptionOnlineEvaluatorNode::PerceptionOnlineEvaluatorNode(
 
 void PerceptionOnlineEvaluatorNode::publishMetrics()
 {
-  DiagnosticArray metrics_msg;
+  // DiagnosticArray metrics_msg;
+  tier4_metric_msgs::msg::MetricArray metrics_msg;
 
   // calculate metrics
   for (const Metric & metric : parameters_->metrics) {
@@ -80,10 +81,10 @@ void PerceptionOnlineEvaluatorNode::publishMetrics()
         for (const auto & [metric, value] : arg) {
           if constexpr (std::is_same_v<T, MetricStatMap>) {
             if (value.count() > 0) {
-              metrics_msg.status.emplace_back(generateDiagnosticStatus(metric, value));
+              toMetricMsg(metric, value, metrics_msg);
             }
           } else if constexpr (std::is_same_v<T, MetricValueMap>) {
-            metrics_msg.status.emplace_back(generateDiagnosticStatus(metric, value));
+            toMetricMsg(metric, value, metrics_msg);
           }
         }
       },
@@ -91,49 +92,44 @@ void PerceptionOnlineEvaluatorNode::publishMetrics()
   }
 
   // publish metrics
-  if (!metrics_msg.status.empty()) {
-    metrics_msg.header.stamp = now();
+  if (!metrics_msg.metric_array.empty()) {
+    metrics_msg.stamp = now();
     metrics_pub_->publish(metrics_msg);
   }
   publishDebugMarker();
 }
 
-DiagnosticStatus PerceptionOnlineEvaluatorNode::generateDiagnosticStatus(
-  const std::string metric, const Accumulator<double> & metric_stat) const
+void PerceptionOnlineEvaluatorNode::toMetricMsg(
+  const std::string & metric, const Accumulator<double> & metric_stat,
+  tier4_metric_msgs::msg::MetricArray & metrics_msg) const
 {
-  DiagnosticStatus status;
-
-  status.level = status.OK;
-  status.name = metric;
-
-  diagnostic_msgs::msg::KeyValue key_value;
-  key_value.key = "min";
-  key_value.value = std::to_string(metric_stat.min());
-  status.values.push_back(key_value);
-  key_value.key = "max";
-  key_value.value = std::to_string(metric_stat.max());
-  status.values.push_back(key_value);
-  key_value.key = "mean";
-  key_value.value = std::to_string(metric_stat.mean());
-  status.values.push_back(key_value);
-
-  return status;
+  // min value
+  metrics_msg.metric_array.emplace_back(tier4_metric_msgs::build<tier4_metric_msgs::msg::Metric>()
+                                          .name(metric + "/min")
+                                          .unit("")
+                                          .value(std::to_string(metric_stat.min())));
+
+  // max value
+  metrics_msg.metric_array.emplace_back(tier4_metric_msgs::build<tier4_metric_msgs::msg::Metric>()
+                                          .name(metric + "/max")
+                                          .unit("")
+                                          .value(std::to_string(metric_stat.max())));
+
+  // mean value
+  metrics_msg.metric_array.emplace_back(tier4_metric_msgs::build<tier4_metric_msgs::msg::Metric>()
+                                          .name(metric + "/mean")
+                                          .unit("")
+                                          .value(std::to_string(metric_stat.mean())));
 }
 
-DiagnosticStatus PerceptionOnlineEvaluatorNode::generateDiagnosticStatus(
-  const std::string & metric, const double value) const
+void PerceptionOnlineEvaluatorNode::toMetricMsg(
+  const std::string & metric, const double metric_value,
+  tier4_metric_msgs::msg::MetricArray & metrics_msg) const
 {
-  DiagnosticStatus status;
-
-  status.level = status.OK;
-  status.name = metric;
-
-  diagnostic_msgs::msg::KeyValue key_value;
-  key_value.key = "metric_value";
-  key_value.value = std::to_string(value);
-  status.values.push_back(key_value);
-
-  return status;
+  metrics_msg.metric_array.emplace_back(tier4_metric_msgs::build<tier4_metric_msgs::msg::Metric>()
+                                          .name(metric + "/metric_value")
+                                          .unit("")
+                                          .value(std::to_string(metric_value)));
 }
 
 void PerceptionOnlineEvaluatorNode::onObjects(const PredictedObjects::ConstSharedPtr objects_msg)
diff --git a/evaluator/perception_online_evaluator/test/test_perception_online_evaluator_node.cpp b/evaluator/perception_online_evaluator/test/test_perception_online_evaluator_node.cpp
index e2ab22be2b61b..5b23f6d37a1d4 100644
--- a/evaluator/perception_online_evaluator/test/test_perception_online_evaluator_node.cpp
+++ b/evaluator/perception_online_evaluator/test/test_perception_online_evaluator_node.cpp
@@ -21,7 +21,7 @@
 
 #include <autoware_perception_msgs/msg/object_classification.hpp>
 #include <autoware_perception_msgs/msg/predicted_objects.hpp>
-#include <diagnostic_msgs/msg/diagnostic_array.hpp>
+#include <tier4_metric_msgs/msg/metric_array.hpp>
 #include <visualization_msgs/msg/marker_array.hpp>
 
 #include "boost/lexical_cast.hpp"
@@ -37,7 +37,6 @@
 using EvalNode = perception_diagnostics::PerceptionOnlineEvaluatorNode;
 using PredictedObjects = autoware_perception_msgs::msg::PredictedObjects;
 using PredictedObject = autoware_perception_msgs::msg::PredictedObject;
-using DiagnosticArray = diagnostic_msgs::msg::DiagnosticArray;
 using MarkerArray = visualization_msgs::msg::MarkerArray;
 using ObjectClassification = autoware_perception_msgs::msg::ObjectClassification;
 using nav_msgs::msg::Odometry;
@@ -125,36 +124,29 @@ class EvalTest : public ::testing::Test
     tf_pub_->publish(tf_msg);
   }
 
-  void setTargetMetric(perception_diagnostics::Metric metric)
+  void setTargetMetric(const perception_diagnostics::Metric & metric)
   {
     const auto metric_str = perception_diagnostics::metric_to_str.at(metric);
     setTargetMetric(metric_str);
   }
 
-  void setTargetMetric(std::string metric_str)
+  void setTargetMetric(const std::string & metric_str)
   {
-    const auto is_target_metric = [metric_str](const auto & status) {
-      return status.name == metric_str;
-    };
-    metric_sub_ = rclcpp::create_subscription<DiagnosticArray>(
+    metric_sub_ = rclcpp::create_subscription<tier4_metric_msgs::msg::MetricArray>(
       eval_node, "/perception_online_evaluator/metrics", 1,
-      [=](const DiagnosticArray::ConstSharedPtr msg) {
-        const auto it = std::find_if(msg->status.begin(), msg->status.end(), is_target_metric);
-        if (it != msg->status.end()) {
-          const auto mean_it = std::find_if(
-            it->values.begin(), it->values.end(),
-            [](const auto & key_value) { return key_value.key == "mean"; });
-          if (mean_it != it->values.end()) {
-            metric_value_ = boost::lexical_cast<double>(mean_it->value);
-          } else {
-            const auto metric_value_it = std::find_if(
-              it->values.begin(), it->values.end(),
-              [](const auto & key_value) { return key_value.key == "metric_value"; });
-            if (metric_value_it != it->values.end()) {
-              metric_value_ = boost::lexical_cast<double>(metric_value_it->value);
-            }
-          }
+      [this, metric_str](const tier4_metric_msgs::msg::MetricArray::ConstSharedPtr msg) {
+        // extract a metric whose name includes metrics_str
+        const auto it = std::find_if(
+          msg->metric_array.begin(), msg->metric_array.end(), [&metric_str](const auto & metric) {
+            return metric.name == metric_str + "/metric_value" ||
+                   metric.name == metric_str + "/mean";
+          });
+
+        if (it != msg->metric_array.end()) {
+          metric_value_ = boost::lexical_cast<double>(it->value);
           metric_updated_ = true;
+        } else {
+          metric_updated_ = false;
         }
       });
   }
@@ -316,7 +308,7 @@ class EvalTest : public ::testing::Test
 
   // Pub/Sub
   rclcpp::Publisher<PredictedObjects>::SharedPtr objects_pub_;
-  rclcpp::Subscription<DiagnosticArray>::SharedPtr metric_sub_;
+  rclcpp::Subscription<tier4_metric_msgs::msg::MetricArray>::SharedPtr metric_sub_;
   rclcpp::Subscription<MarkerArray>::SharedPtr marker_sub_;
   rclcpp::Publisher<TFMessage>::SharedPtr tf_pub_;
   bool has_received_marker_{false};