diff --git a/CHANGELOG.md b/CHANGELOG.md
index 640079a..eb04556 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ---
 
 ## [1.1.1](https://github.com/kakaopensource/KakaJSON/releases/tag/1.1.1) (2019-11-04)
+- Adjust Lock
 - Closed issues
 	- [iOS 9 Crash](https://github.com/kakaopensource/KakaJSON/issues/31)
 - Merged pull requests
diff --git a/Sources/KakaJSON/Metadata/Metadata.swift b/Sources/KakaJSON/Metadata/Metadata.swift
index 71acd95..6555a4b 100644
--- a/Sources/KakaJSON/Metadata/Metadata.swift
+++ b/Sources/KakaJSON/Metadata/Metadata.swift
@@ -13,6 +13,9 @@ public struct Metadata {
     private static var types = [TypeKey: BaseType]()
     
     public static func type(_ type: Any.Type) -> BaseType? {
+        typeLock.lock()
+        defer { typeLock.unlock() }
+        
         // get from cache
         let key = typeKey(type)
         if let mt = types[key] { return mt }
@@ -23,11 +26,6 @@ public struct Metadata {
             || name == "NSObject"
             || name == "_TtCs12_SwiftObject" { return nil }
         
-        typeLock.lock()
-        defer { typeLock.unlock() }
-        // judge after lock
-        if let mt = types[key] { return mt }
-        
         // type judge
         var mtt: BaseType.Type
         let kind = Kind(type)
diff --git a/Sources/KakaJSON/Metadata/Type/ModelType.swift b/Sources/KakaJSON/Metadata/Type/ModelType.swift
index c428015..e07064c 100644
--- a/Sources/KakaJSON/Metadata/Type/ModelType.swift
+++ b/Sources/KakaJSON/Metadata/Type/ModelType.swift
@@ -18,8 +18,6 @@ public class ModelType: BaseType {
     
     func modelKey(from propertyName: String,
                   _ createdKey: @autoclosure () -> ModelPropertyKey) -> ModelPropertyKey {
-        if let key = modelKeys[propertyName] { return key }
-        
         modelKeysLock.wait()
         defer { modelKeysLock.signal() }
         if let key = modelKeys[propertyName] { return key }
@@ -31,8 +29,6 @@ public class ModelType: BaseType {
     
     func JSONKey(from propertyName: String,
                  _ createdKey: @autoclosure () -> String) -> String {
-        if let key = jsonKeys[propertyName] { return key }
-        
         jsonKeysLock.wait()
         defer { jsonKeysLock.signal() }
         if let key = jsonKeys[propertyName] { return key }