diff --git a/NineChroniclesUtilBackend/Controllers/AvatarController.cs b/NineChroniclesUtilBackend/Controllers/AvatarController.cs
index 2c44eabb..de02ea07 100644
--- a/NineChroniclesUtilBackend/Controllers/AvatarController.cs
+++ b/NineChroniclesUtilBackend/Controllers/AvatarController.cs
@@ -9,6 +9,15 @@ namespace NineChroniclesUtilBackend.Controllers;
 public class AvatarController(AvatarRepository avatarRepository) : ControllerBase
 {
     [HttpGet("{avatarAddress}/inventory")]
-    public Inventory GetInventory(string avatarAddress) =>
-        avatarRepository.GetInventory(avatarAddress);
+    public Inventory? GetInventory(string avatarAddress)
+    {
+        var inventory = avatarRepository.GetInventory(avatarAddress);
+        if (inventory is null)
+        {
+            Response.StatusCode = StatusCodes.Status404NotFound;
+            return null;
+        }
+
+        return inventory;
+    }
 }
diff --git a/NineChroniclesUtilBackend/Repositories/AvatarRepository.cs b/NineChroniclesUtilBackend/Repositories/AvatarRepository.cs
index 48224c33..9242e6b3 100644
--- a/NineChroniclesUtilBackend/Repositories/AvatarRepository.cs
+++ b/NineChroniclesUtilBackend/Repositories/AvatarRepository.cs
@@ -10,11 +10,16 @@ public class AvatarRepository(MongoDBCollectionService mongoDBCollectionService)
     private readonly IMongoCollection<BsonDocument> _avatarsCollection =
         mongoDBCollectionService.GetCollection<BsonDocument>("avatars");
 
-    public Inventory GetInventory(string avatarAddress)
+    public Inventory? GetInventory(string avatarAddress)
     {
         var filter = Builders<BsonDocument>.Filter.Eq(f => f["Avatar"]["address"], avatarAddress);
         var projection = Builders<BsonDocument>.Projection.Include(f => f["Avatar"]["inventory"]["Equipments"]);
         var document = _avatarsCollection.Find(filter).Project(projection).FirstOrDefault();
+        if (document is null)
+        {
+            return null;
+        }
+        
         return new Inventory(document["Avatar"]["inventory"]);
     }
 }