diff --git a/RxJava/practice/src/main/java/org/example/ex05/CompletableCreateEx.java b/RxJava/practice/src/main/java/org/example/ex05/CompletableCreateEx.java
new file mode 100644
index 00000000..75a7ca9f
--- /dev/null
+++ b/RxJava/practice/src/main/java/org/example/ex05/CompletableCreateEx.java
@@ -0,0 +1,52 @@
+package org.example.ex05;
+
+import io.reactivex.rxjava3.core.Completable;
+import io.reactivex.rxjava3.core.CompletableEmitter;
+import io.reactivex.rxjava3.core.CompletableObserver;
+import io.reactivex.rxjava3.core.CompletableOnSubscribe;
+import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.schedulers.Schedulers;
+import org.example.utils.LogType;
+import org.example.utils.Logger;
+import org.example.utils.TimeUtil;
+
+/**
+ * Completable 을 사용하여 어떤 작업을 수행한 후, 완료를 통지하는 예제
+ */
+public class CompletableCreateEx {
+    public static void main(String[] args) throws InterruptedException {
+        Completable completable = Completable.create(new CompletableOnSubscribe() {
+            @Override
+            public void subscribe(CompletableEmitter emitter) throws Exception {
+                // 데이터를 통지하는것이 아니라 특정 작업을 수행한 후, 완료를 통지한다.
+                int sum = 0;
+                for(int i =0; i < 100; i++){
+                    sum += i;
+                }
+                Logger.log(LogType.PRINT, "# 합계: " + sum);
+
+                emitter.onComplete();
+            }
+        });
+
+        completable.subscribeOn(Schedulers.computation())
+                .subscribe(new CompletableObserver() {
+            @Override
+            public void onSubscribe(Disposable disposable) {
+                // 아무것도 하지 않음
+            }
+
+            @Override
+            public void onComplete() {
+                Logger.log(LogType.ON_COMPLETE);
+            }
+
+            @Override
+            public void onError(Throwable error) {
+                Logger.log(LogType.ON_ERROR, error);
+            }
+        });
+
+        TimeUtil.sleep(1000L);
+    }
+}
\ No newline at end of file
diff --git a/RxJava/practice/src/main/java/org/example/ex05/CompletableLamdaEx.java b/RxJava/practice/src/main/java/org/example/ex05/CompletableLamdaEx.java
new file mode 100644
index 00000000..24636218
--- /dev/null
+++ b/RxJava/practice/src/main/java/org/example/ex05/CompletableLamdaEx.java
@@ -0,0 +1,30 @@
+package org.example.ex05;
+
+import io.reactivex.rxjava3.core.Completable;
+import io.reactivex.rxjava3.schedulers.Schedulers;
+import org.example.utils.LogType;
+import org.example.utils.Logger;
+import org.example.utils.TimeUtil;
+
+public class CompletableLamdaEx {
+    public static void main(String[] args){
+        Completable completable = Completable.create(emitter -> {
+            // 데이터를 발행하는것이 아니라 특정 작업을 수행한 후, 완료를 통지한다.
+            int sum = 0;
+            for(int i =0; i < 100; i++){
+                sum += i;
+            }
+            Logger.log(LogType.PRINT, "# 합계: " + sum);
+
+            emitter.onComplete();
+        });
+
+        completable.subscribeOn(Schedulers.computation())
+                .subscribe(
+                        () -> Logger.log(LogType.ON_COMPLETE),
+                        error -> Logger.log(LogType.ON_ERROR, error)
+                );
+
+        TimeUtil.sleep(1000L);
+    }
+}
\ No newline at end of file