diff --git a/Assets/VRM/UniJSON/Scripts/Json/JsonSchema.cs b/Assets/VRM/UniJSON/Scripts/Json/JsonSchema.cs
index be73d4102..1957c4119 100644
--- a/Assets/VRM/UniJSON/Scripts/Json/JsonSchema.cs
+++ b/Assets/VRM/UniJSON/Scripts/Json/JsonSchema.cs
@@ -58,6 +58,7 @@ namespace UniJSON
         public bool SkipComparison { get; set; }
 
         public object ExplicitIgnorableValue { private get; set; }
+        public int ExplicitIgnorableItemLength { private get; set; }
 
         public override string ToString()
         {
@@ -179,6 +180,7 @@ namespace UniJSON
                 Validator = validator,
                 SkipComparison = skipComparison,
                 ExplicitIgnorableValue = a.ExplicitIgnorableValue,
+                ExplicitIgnorableItemLength = a.ExplicitIgnorableItemLength,
             };
 
             return schema;
@@ -386,9 +388,12 @@ namespace UniJSON
         }
         #endregion
 
-        public void Serialize<T>(IFormatter f, T o)
+        public void Serialize<T>(IFormatter f, T o, JsonSchemaValidationContext c = null)
         {
-            var c = new JsonSchemaValidationContext(o);
+            if (c == null)
+            {
+                c = new JsonSchemaValidationContext(o);
+            }
 
             var ex = Validator.Validate(c, o);
             if (ex != null)
@@ -415,16 +420,22 @@ namespace UniJSON
                 return ExplicitIgnorableValue == null;
             }
 
+            var iter = obj as System.Collections.ICollection;
+            if (ExplicitIgnorableItemLength != -1 && iter != null)
+            {
+                return iter.Count == ExplicitIgnorableItemLength;
+            }
+
             return obj.Equals(ExplicitIgnorableValue);
         }
     }
 
     public static class JsonSchemaExtensions
     {
-        public static string Serialize<T>(this JsonSchema s, T o)
+        public static string Serialize<T>(this JsonSchema s, T o, JsonSchemaValidationContext c = null)
         {
             var f = new JsonFormatter();
-            s.Serialize(f, o);
+            s.Serialize(f, o, c);
             return f.ToString();
         }
     }
diff --git a/Assets/VRM/UniJSON/Scripts/Json/JsonSchemaAttribute.cs b/Assets/VRM/UniJSON/Scripts/Json/JsonSchemaAttribute.cs
index f7ebad56a..4e44ebea2 100644
--- a/Assets/VRM/UniJSON/Scripts/Json/JsonSchemaAttribute.cs
+++ b/Assets/VRM/UniJSON/Scripts/Json/JsonSchemaAttribute.cs
@@ -61,6 +61,12 @@ namespace UniJSON
         /// </summary>
         public object ExplicitIgnorableValue;
 
+        /// <summary>
+        /// Suppress errors if length of a value of the field which is not required by a schema is matched to this value.
+        /// This feature will be useful to ignore invalid value which is known.
+        /// </summary>
+        public int ExplicitIgnorableItemLength = -1;
+
         public void Merge(BaseJsonSchemaAttribute rhs)
         {
             if (rhs == null) return;