diff --git a/TakayunAverage.h b/TakayunAverage.h
new file mode 100644
index 0000000..8bcd71e
--- /dev/null
+++ b/TakayunAverage.h
@@ -0,0 +1,55 @@
+#pragma once
+
+#define TAKAYUN_AVERAGE_DEBUG__DISABLE
+
+#include <iostream>
+using namespace std;
+
+template <typename T>
+class TakayunAverage {
+private:
+  T sum, *buff, average;
+  int buff_size, index;
+
+  void initialize(int buff_size) {
+    this->buff_size = buff_size;
+    buff = new T[buff_size];
+    for (int i = 0; i < buff_size; i++) buff[i] = 0;
+    index = sum = average = 0;
+  }
+
+  T update_average(T data) {
+#ifdef TAKAYUN_AVERAGE_DEBUG__ENABLE
+    cout << "[TakayunAverage::update_average]: ";
+    for (int i = 0; i < buff_size; i++) cout << buff[i] << " ";
+    cout << endl;
+#endif
+    static T first;
+    index++;
+    if (!(index < buff_size)) index = 0;
+    first = buff[index];
+    buff[index] = data;
+    sum = sum - first + data;
+    average = sum / buff_size;
+    return average;
+  }
+
+public:
+  TakayunAverage(int buff_size) {
+    initialize(buff_size);
+  }
+  TakayunAverage(int buff_size, T initial_value) {
+    initialize(buff_size);
+    for (int i = 0; i < buff_size; i++) update_average(initial_value);
+  }
+  ~TakayunAverage() {
+    delete[] buff;
+  }
+  
+  T get_average() {
+    return average;
+  }
+  T get_average(T data) {
+    return update_average(data);
+  }
+};
diff --git a/example1.cpp b/example1.cpp
new file mode 100644
index 0000000..8827822
--- /dev/null
+++ b/example1.cpp
@@ -0,0 +1,15 @@
+//#define TAKAYUN_AVERAGE_DEBUG__ENABLE
+#include "TakayunAverage.h"
+
+int main() {
+   /* TakayunAverage<T>(int buff_size)
+    * TakayunAverage<T>(int buff_size, T initial_average_value)
+    */
+  TakayunAverage<int> ca(10);
+  cout << ca.get_average(1) << endl;
+  cout << ca.get_average(2) << endl;
+  cout << ca.get_average(3) << endl;
+  cout << ca.get_average(4) << endl;
+  cout << ca.get_average(5) << endl;
+  return 0;
+}
diff --git a/example2.cpp b/example2.cpp
new file mode 100644
index 0000000..dba82e2
--- /dev/null
+++ b/example2.cpp
@@ -0,0 +1,11 @@
+#include "TakayunAverage.h"
+
+int main() {
+  TakayunAverage<int> *ca = new TakayunAverage<int>(3, 12);
+  cout << ca->get_average(1) << endl;
+  cout << ca->get_average(2) << endl;
+  cout << ca->get_average(3) << endl;
+  cout << ca->get_average(4) << endl;
+  cout << ca->get_average(5) << endl;
+  return 0;
+}