diff --git a/src/main/java/cactusServer/models/CollisionManager.java b/src/main/java/cactusServer/models/CollisionManager.java
index c56b316..3ffe8f1 100644
--- a/src/main/java/cactusServer/models/CollisionManager.java
+++ b/src/main/java/cactusServer/models/CollisionManager.java
@@ -2,11 +2,15 @@
 
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.Map;
+
 import org.ntlab.radishforandroidstudio.framework.model3D.CollisionResult;
+import org.ntlab.radishforandroidstudio.framework.model3D.Object3D;
 import org.ntlab.radishforandroidstudio.framework.model3D.Position3D;
 import org.ntlab.radishforandroidstudio.framework.physics.PhysicsUtility;
 import org.ntlab.radishforandroidstudio.java3d.Vector3d;
 
+import cactusServer.entities.Bullet;
 import cactusServer.entities.Instance;
 import cactusServer.entities.Object;
 import cactusServer.entities.Player;
@@ -40,6 +44,7 @@
 			Instance instance = Instances.getInstance().getInstance(instanceId);
 			instance.getUniverse().update(interval);
 			collisionPlayersObjects(instanceId, instance);
+			collisionBulletsAndOthers(instanceId, instance);
 		}
 	}
 
@@ -86,4 +91,49 @@
 		vec.add(result.normal);
 		object.setPosition(new Position3D(vec));
 	}
+	
+	private void collisionBulletsAndOthers(String instanceId, Instance instance) {
+		for (Map.Entry<String, HashMap<String, Bullet>> playersBulletsEntry : instance.getBullets().entrySet()) {
+			String bulletOwnerPlayerId = playersBulletsEntry.getKey();
+			Map<String, Bullet> bulletMap = playersBulletsEntry.getValue();
+			for (Map.Entry<String, Bullet> bulletEntry : bulletMap.entrySet()) {
+				String bulletId = bulletEntry.getKey();
+				Bullet bullet = bulletEntry.getValue();
+				collisionBulletAndPlayers(instanceId, instance, bulletOwnerPlayerId, bulletId, bullet);
+				collisionBulletAndObjects(instance, bulletOwnerPlayerId, bulletId, bullet);
+			}
+		}
+	}
+	
+	private void collisionBulletAndPlayers(String instanceId, Instance instance, String bulletOwnerPlayerId, String bulletId, Bullet bullet) {
+		Instances instances = Instances.getInstance();
+		for (Map.Entry<String, Player> playersEntry : instances.getPlayers(instanceId).entrySet()) {
+			if (isCollision(bullet, playersEntry.getValue())) {
+				if (!(playersEntry.getKey().equals(bulletOwnerPlayerId))) {
+					// Player(����������)�ƒe�������������̏���������
+				}
+				instance.destroyBullet(bulletOwnerPlayerId, bulletId); // Player(�������܂�)�ɓ��������e������
+			}
+		}
+	}
+	
+	private void collisionBulletAndObjects(Instance instance, String bulletOwnerPlayerId, String bulletId, Bullet bullet) {
+		for (Object object : instance.getObjects().values()) {
+			if (isCollision(bullet, object)) {
+				instance.destroyBullet(bulletOwnerPlayerId, bulletId);
+			}
+		}
+	}
+	
+	private boolean isCollision(Bullet bullet, Player player) {
+		CollisionResult result;
+		result = PhysicsUtility.checkCollision((Object3D) (bullet.getPlaceable()), null, player.getObject(), null);
+		return (result != null);
+	}
+	
+	private boolean isCollision(Bullet bullet, Object object) {
+		CollisionResult result;
+		result = PhysicsUtility.checkCollision((Object3D) (bullet.getPlaceable()), null, object.getObject(), null);
+		return (result != null);
+	}
 }