diff --git a/localization/ndt_scan_matcher/src/ndt_scan_matcher_core.cpp b/localization/ndt_scan_matcher/src/ndt_scan_matcher_core.cpp
index 697a9e5efed30..5d06c0bc1dbc7 100644
--- a/localization/ndt_scan_matcher/src/ndt_scan_matcher_core.cpp
+++ b/localization/ndt_scan_matcher/src/ndt_scan_matcher_core.cpp
@@ -1033,7 +1033,7 @@ geometry_msgs::msg::PoseWithCovarianceStamped NDTScanMatcher::align_pose(
     base_rpy.x,                                  // angle_x
     base_rpy.y                                   // angle_y
   };
-  std::vector<double> sample_stddev{stddev_x, stddev_y, stddev_z, stddev_roll, stddev_pitch};
+  const std::vector<double> sample_stddev{stddev_x, stddev_y, stddev_z, stddev_roll, stddev_pitch};
 
   // Optimizing (x, y, z, roll, pitch, yaw) 6 dimensions.
   TreeStructuredParzenEstimator tpe(