diff --git a/start.sh b/start.sh
index ccd9e7b..5bd7770 100644
--- a/start.sh
+++ b/start.sh
@@ -6,9 +6,10 @@ IS_MANUAL_CONTROLL="n"
 IS_SAMPLE_CONTROLL="n"
 GAME_TIME="180"                  # game time (s)
 RESULT_LOG_JSON="result.json"    # result log file
+INPUT_RAMDOM_SEED=""             # random seed
 
 ## get args level setting
-while getopts l:m:s:t:f: OPT
+while getopts l:m:s:t:f:r: OPT
 do
   case $OPT in
     "l" ) VALUE_L="$OPTARG" ;;
@@ -16,6 +17,7 @@ do
     "s" ) IS_SAMPLE_CONTROLL="$OPTARG" ;;
     "t" ) GAME_TIME="$OPTARG" ;;
     "f" ) RESULT_LOG_JSON="$OPTARG" ;;
+    "r" ) INPUT_RAMDOM_SEED="$OPTARG" ;;
   esac
 done
 echo "level: $VALUE_L"
@@ -34,6 +36,11 @@ case $VALUE_L in
     "3" ) RANDOM_SEED="-1"; OBSTACLE_HEIGHT="10"; OBSTACLE_PROBABILITY="40"; ;;
     * ) echo "invalid level: $VALUE_L"; exit 1;;
 esac
+
+if [ ! -z ${INPUT_RAMDOM_SEED} ]; then
+    # fix random seed from given value.
+    RANDOM_SEED=${INPUT_RAMDOM_SEED}
+fi
 echo "game_time: $GAME_TIME"
 echo "RANDOM_SEED: $RANDOM_SEED"
 echo "OBSTACLE_HEIGHT: ${OBSTACLE_HEIGHT}"