diff --git a/sciurus17_control/src/sciurus17_hardware.cpp b/sciurus17_control/src/sciurus17_hardware.cpp
index bd21e4a..3016954 100644
--- a/sciurus17_control/src/sciurus17_hardware.cpp
+++ b/sciurus17_control/src/sciurus17_hardware.cpp
@@ -235,7 +235,7 @@ return_type Sciurus17Hardware::read(
     return return_type::ERROR;
   }
 
-  for (auto group_name : GROUP_NAMES) {
+  for (const auto & group_name : GROUP_NAMES) {
     if (!hardware_->sync_read(group_name)) {
       RCLCPP_ERROR(LOGGER, "Failed to sync read from servo motors.");
       // sync_readに失敗しても通信は継続させる。