diff --git a/build.gradle.kts b/build.gradle.kts
index 67e5a3b..35c008f 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -9,7 +9,7 @@ plugins {
 }
 
 group = "net.azisaba"
-version = "6.7.1"
+version = "6.7.2"
 
 java {
     toolchain.languageVersion.set(JavaLanguageVersion.of(8))
diff --git a/src/main/java/com/github/mori01231/lifecore/command/GCListenerRestartExtendTimeCommand.java b/src/main/java/com/github/mori01231/lifecore/command/GCListenerRestartExtendTimeCommand.java
index c5c791b..e862514 100644
--- a/src/main/java/com/github/mori01231/lifecore/command/GCListenerRestartExtendTimeCommand.java
+++ b/src/main/java/com/github/mori01231/lifecore/command/GCListenerRestartExtendTimeCommand.java
@@ -26,6 +26,10 @@ public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command
             return true;
         }
         Player player = (Player) sender;
+        if (players.contains(player.getUniqueId())) {
+            sender.sendMessage(ChatColor.RED + "すでに投票済みです。");
+            return true;
+        }
         players.add(player.getUniqueId());
         sender.sendMessage(ChatColor.GREEN + "投票しました。");
         if (sender.hasPermission("lifecore.extend-time-immediately") || players.size() == 5) {