diff --git a/src/motion/cubismmotionjson.ts b/src/motion/cubismmotionjson.ts
index ee55db0..eace15b 100644
--- a/src/motion/cubismmotionjson.ts
+++ b/src/motion/cubismmotionjson.ts
@@ -8,7 +8,6 @@
 import { CubismIdHandle } from '../id/cubismid';
 import { CubismFramework } from '../live2dcubismframework';
 import { csmString } from '../type/csmstring';
-import { csmVector } from '../type/csmvector';
 import { CubismJson } from '../utils/cubismjson';
 
 // JSON keys
@@ -226,12 +225,12 @@ export class CubismMotionJson {
    * @return false 存在しない
    */
   public isExistMotionCurveFadeInTime(curveIndex: number): boolean {
-    const value = this._json
+    return !this._json
       .getRoot()
       .getValueByString(Curves)
       .getValueByIndex(curveIndex)
-      .getValueByString(FadeInTime);
-    return !(value.isNull() || value.isError());
+      .getValueByString(FadeInTime)
+      .isNull();
   }
 
   /**
@@ -241,12 +240,12 @@ export class CubismMotionJson {
    * @return false 存在しない
    */
   public isExistMotionCurveFadeOutTime(curveIndex: number): boolean {
-    const value = this._json
+    return !this._json
       .getRoot()
       .getValueByString(Curves)
       .getValueByIndex(curveIndex)
-      .getValueByString(FadeOutTime);
-    return !(value.isNull() || value.isError());
+      .getValueByString(FadeOutTime)
+      .isNull();
   }
 
   /**
@@ -288,7 +287,7 @@ export class CubismMotionJson {
       .getValueByString(Curves)
       .getValueByIndex(curveIndex)
       .getValueByString(Segments)
-      .getVector(new csmVector())
+      .getVector()
       .getSize();
   }
 
diff --git a/src/utils/cubismjson.ts b/src/utils/cubismjson.ts
index c05d33d..d8097a0 100644
--- a/src/utils/cubismjson.ts
+++ b/src/utils/cubismjson.ts
@@ -74,7 +74,7 @@ export abstract class Value {
   /**
    * 要素をコンテナで返す(array)
    */
-  public getVector(defaultValue?: csmVector<Value>): csmVector<Value> {
+  public getVector(defaultValue = new csmVector<Value>()): csmVector<Value> {
     return defaultValue;
   }
 
@@ -192,11 +192,8 @@ export abstract class Value {
   public static staticInitializeNotForClientCall(): void {
     JsonBoolean.trueValue = new JsonBoolean(true);
     JsonBoolean.falseValue = new JsonBoolean(false);
-
-    JsonError.errorValue = new JsonError('ERROR', true);
-    this.nullValue = new JsonNullvalue();
-    this.errorValue = new JsonError('ERROR', true);
-
+    Value.errorValue = new JsonError('ERROR', true);
+    Value.nullValue = new JsonNullvalue();
     Value.s_dummyKeys = new csmVector<string>();
   }
 
@@ -206,13 +203,7 @@ export abstract class Value {
   public static staticReleaseNotForClientCall(): void {
     JsonBoolean.trueValue = null;
     JsonBoolean.falseValue = null;
-    JsonError.errorValue = null;
-    Value.nullValue = null;
-    Value.s_dummyKeys = null;
-
-    JsonBoolean.trueValue = null;
-    JsonBoolean.falseValue = null;
-    JsonError.errorValue = null;
+    Value.errorValue = null;
     Value.nullValue = null;
     Value.s_dummyKeys = null;
   }
@@ -971,6 +962,14 @@ export class JsonNullvalue extends Value {
     return true;
   }
 
+  /**
+   * Valueにエラー値をセットする
+   */
+  public setErrorNotForClientCall(s: string): Value {
+    this._stringBuffer = s;
+    return JsonError.nullValue;
+  }
+
   /**
    * コンストラクタ
    */