diff --git a/include/queue/queue.hpp b/include/queue/queue.hpp
index 05f2dfe..81c4d4e 100644
--- a/include/queue/queue.hpp
+++ b/include/queue/queue.hpp
@@ -8,6 +8,7 @@ class Queue {
 private:
     int sp;
     int ep;
+    int count;
     Data* buffer;
 public:
     Queue();
diff --git a/include/queue/queue.tpp b/include/queue/queue.tpp
index b7f341c..ac9353e 100644
--- a/include/queue/queue.tpp
+++ b/include/queue/queue.tpp
@@ -1,7 +1,7 @@
 #include "queue/queue.hpp"
 
 template<class Data>
-Queue<Data>::Queue() : sp(0), ep(0) {
+Queue<Data>::Queue() : sp(0), ep(0), count(0){
     buffer = new Data[QUEUE_SIZE];
 }
 
@@ -14,23 +14,38 @@ template<class Data>
 void Queue<Data>::clear() {
     sp = 0;
     ep = 0;
+    count = 0;
 }
 
 template<class Data>
 void Queue<Data>::push(Data data) {
+    if (count == QUEUE_SIZE) {
+        sp = (sp + 1) % QUEUE_SIZE;
+    } else {
+        count++;
+    }
+
+    buffer[ep] = data;
+    ep = (ep + 1) % QUEUE_SIZE;
 }
 
 template<class Data>
 Data Queue<Data>::pull() {
-    return buffer[sp];
+    if (count == 0) throw std::underflow_error("Queue is empty");
+
+    Data data = buffer[sp];
+    sp = (sp + 1) % QUEUE_SIZE;
+    count--;
+    return data;
 }
 
 template<class Data>
 Data Queue<Data>::top() {
+    if (count == 0) throw std::underflow_error("Queue is empty");
     return buffer[sp];
 }
 
 template<class Data>
 int Queue<Data>::size() {
-    return 0;
+    return (ep - sp + QUEUE_SIZE) % QUEUE_SIZE;
 }
\ No newline at end of file
diff --git a/test/queue/queue_test.cpp b/test/queue/queue_test.cpp
index 53b76a1..89e8a5d 100644
--- a/test/queue/queue_test.cpp
+++ b/test/queue/queue_test.cpp
@@ -42,4 +42,27 @@ TEST_F(QueueTest, push_and_pull) {
 
     // then
     EXPECT_EQ(second, v2);
+}
+
+
+TEST_F(QueueTest, throw_exception_when_empty) {
+    // 큐가 비어있는 상태에서
+    int_queue.clear();
+
+    // 에러가 발생하는지 확인
+    EXPECT_THROW(int_queue.pull(), std::underflow_error);
+    EXPECT_THROW(int_queue.top(), std::underflow_error);
+}
+
+
+TEST_F(QueueTest, throw_exception_when_full) {
+    // 큐를 가득 채움 (QUEUE_SIZE가 20이라고 가정)
+    for(int i = 0; i < 30; i++) {
+        int_queue.push(i);
+    }
+
+    for (int i = 10; i < 30; i++) {
+        EXPECT_EQ(int_queue.pull(), i);
+    }
+    
 }
\ No newline at end of file