diff --git a/webapp/services/BattleBoxService.php b/webapp/services/BattleBoxService.php
index 8bc3e2b2..2c54974b 100644
--- a/webapp/services/BattleBoxService.php
+++ b/webapp/services/BattleBoxService.php
@@ -22,7 +22,7 @@ class BattleBoxService {
         $alreadyAllocNum = self::getDailyPhaseAlreadyAllocNum($currPhase, myself()->_getNowDaySeconds());
         if ($allocableNum > 0) {
             $lstVal = mt\Parameter::getListValue('battle_event_loot_per_game');
-            if (!$allocableNum <= 0 || empty($lstVal) || count($lstVal) < 2) {
+            if (!($allocableNum <= 0 || empty($lstVal) || count($lstVal) < 2)) {
                 $rnd = rand($lstVal[0], $lstVal[1]);
                 if ($rnd > 0) {
                     $boxNum = min($rnd, $allocableNum);