diff --git a/StockingData/Lib/Math/AverageMath.cs b/StockingData/Lib/Math/AverageMath.cs
index 4c7863c..4b55b2c 100644
--- a/StockingData/Lib/Math/AverageMath.cs
+++ b/StockingData/Lib/Math/AverageMath.cs
@@ -4,6 +4,12 @@ public static class AverageMath
 {
     public static double Average(IEnumerable<int> values)
     {
+        // 0件の時、NaNになるため、対応
+        if (values.Count() == 0)
+        {
+            return 0;
+        }
+
         double sum = values.Sum();
         return sum / values.Count();
     }