diff --git a/jsk_unitree_robot/cross/install.sh b/jsk_unitree_robot/cross/install.sh
index 56da7c1b6f..2ac8a123f4 100755
--- a/jsk_unitree_robot/cross/install.sh
+++ b/jsk_unitree_robot/cross/install.sh
@@ -54,7 +54,7 @@ function copy_data () {
     fi
 
     # Check if robot is reachable
-    reachability=$(ping -c4 ${hostname} 2>/dev/null | awk '/---/,0' | grep -Po '[0-9]{1,3}(?=% packet loss)')
+    reachability=$(LANG=C ping -c4 ${hostname} 2>/dev/null | awk '/---/,0' | grep -Po '[0-9]{1,3}(?=% packet loss)')
     if [ -z "$reachability" ] || [ "$reachability" == 100 ]; then
         echo "ERROR: ${hostname} unreachable" 1>&2
         exit 2