diff --git a/src/afterfact.rs b/src/afterfact.rs
index 9cdad1aa..c1e1e65a 100644
--- a/src/afterfact.rs
+++ b/src/afterfact.rs
@@ -25,9 +25,11 @@ pub struct CsvFormat<'a> {
 
 pub fn after_fact() {
     let fn_emit_csv_err = |err: Box<dyn Error>| {
-        let stdout = std::io::stdout();
-        let mut stdout = stdout.lock();
-        AlertMessage::alert(&mut stdout, format!("Failed to write CSV. {}", err)).ok();
+        AlertMessage::alert(
+            &mut std::io::stderr().lock(),
+            format!("Failed to write CSV. {}", err),
+        )
+        .ok();
         process::exit(1);
     };
 
@@ -56,9 +58,11 @@ pub fn after_fact() {
             match File::create(csv_path) {
                 Ok(file) => Box::new(file),
                 Err(err) => {
-                    let stdout = std::io::stdout();
-                    let mut stdout = stdout.lock();
-                    AlertMessage::alert(&mut stdout, format!("Failed to open file. {}", err)).ok();
+                    AlertMessage::alert(
+                        &mut std::io::stderr().lock(),
+                        format!("Failed to open file. {}", err),
+                    )
+                    .ok();
                     process::exit(1);
                 }
             }
diff --git a/src/detections/detection.rs b/src/detections/detection.rs
index c3a59c38..cc22aee4 100644
--- a/src/detections/detection.rs
+++ b/src/detections/detection.rs
@@ -51,9 +51,11 @@ impl Detection {
         let mut rulefile_loader = ParseYaml::new();
         let resutl_readdir = rulefile_loader.read_dir(DIRPATH_RULES, &level);
         if resutl_readdir.is_err() {
-            let stdout = std::io::stdout();
-            let mut stdout = stdout.lock();
-            AlertMessage::alert(&mut stdout, format!("{}", resutl_readdir.unwrap_err())).ok();
+            AlertMessage::alert(
+                &mut std::io::stderr().lock(),
+                format!("{}", resutl_readdir.unwrap_err()),
+            )
+            .ok();
             return vec![];
         }
 
@@ -65,14 +67,12 @@ impl Detection {
 
             // ruleファイルのパースに失敗した場合はエラー出力
             err_msgs_result.err().iter().for_each(|err_msgs| {
-                let stdout = std::io::stdout();
-                let mut stdout = stdout.lock();
                 let errmsg_body =
                     format!("Failed to parse Rule file. (FilePath : {})", rule.rulepath);
-                AlertMessage::alert(&mut stdout, errmsg_body).ok();
+                AlertMessage::alert(&mut std::io::stderr().lock(), errmsg_body).ok();
 
                 err_msgs.iter().for_each(|err_msg| {
-                    AlertMessage::alert(&mut stdout, err_msg.to_string()).ok();
+                    AlertMessage::alert(&mut std::io::stderr().lock(), err_msg.to_string()).ok();
                 });
                 println!(""); // 一行開けるためのprintln
             });
diff --git a/src/detections/rule/count.rs b/src/detections/rule/count.rs
index fcc57c79..de1efaf2 100644
--- a/src/detections/rule/count.rs
+++ b/src/detections/rule/count.rs
@@ -69,10 +69,8 @@ pub fn create_count_key(rule: &RuleNode, record: &Value) -> String {
                 key.push_str(&value.to_string().replace("\"", ""));
             }
             None => {
-                let stdout = std::io::stdout();
-                let mut stdout = stdout.lock();
                 AlertMessage::alert(
-                    &mut stdout,
+                    &mut std::io::stderr().lock(),
                     format!("field_value alias not found.value:{}", field_value),
                 )
                 .ok();
@@ -87,10 +85,8 @@ pub fn create_count_key(rule: &RuleNode, record: &Value) -> String {
                 key.push_str(&value.to_string().replace("\"", ""));
             }
             None => {
-                let stdout = std::io::stdout();
-                let mut stdout = stdout.lock();
                 AlertMessage::alert(
-                    &mut stdout,
+                    &mut std::io::stderr().lock(),
                     format!("by_field_value alias not found.value:{}", by_field_value),
                 )
                 .ok();
@@ -177,10 +173,8 @@ impl TimeFrameInfo {
             ttype = "d".to_owned();
             tnum.retain(|c| c != 'd');
         } else {
-            let stdout = std::io::stdout();
-            let mut stdout = stdout.lock();
             AlertMessage::alert(
-                &mut stdout,
+                &mut std::io::stderr().lock(),
                 format!("timeframe is invalid.input value:{}", value),
             )
             .ok();
@@ -211,10 +205,8 @@ pub fn get_sec_timeframe(timeframe: &Option<TimeFrameInfo>) -> Option<i64> {
             }
         }
         Err(err) => {
-            let stdout = std::io::stdout();
-            let mut stdout = stdout.lock();
             AlertMessage::alert(
-                &mut stdout,
+                &mut std::io::stderr().lock(),
                 format!("timeframe num is invalid. timeframe.{}", err),
             )
             .ok();
diff --git a/src/main.rs b/src/main.rs
index 0705ea5f..98bdd7ef 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -30,10 +30,8 @@ fn main() {
     let analysis_start_time: DateTime<Utc> = Utc::now();
     if let Some(filepath) = configs::CONFIG.read().unwrap().args.value_of("filepath") {
         if !filepath.ends_with(".evtx") {
-            let stdout = std::io::stdout();
-            let mut stdout = stdout.lock();
             AlertMessage::alert(
-                &mut stdout,
+                &mut std::io::stderr().lock(),
                 "--filepath is only accepted evtx file.".to_owned(),
             )
             .ok();
@@ -43,9 +41,11 @@ fn main() {
     } else if let Some(directory) = configs::CONFIG.read().unwrap().args.value_of("directory") {
         let evtx_files = collect_evtxfiles(&directory);
         if evtx_files.len() == 0 {
-            let stdout = std::io::stdout();
-            let mut stdout = stdout.lock();
-            AlertMessage::alert(&mut stdout, "No exist evtx file.".to_owned()).ok();
+            AlertMessage::alert(
+                &mut std::io::stderr().lock(),
+                "No exist evtx file.".to_owned(),
+            )
+            .ok();
             return;
         }
         analysis_files(evtx_files);
@@ -62,9 +62,9 @@ fn main() {
 fn collect_evtxfiles(dirpath: &str) -> Vec<PathBuf> {
     let entries = fs::read_dir(dirpath);
     if entries.is_err() {
-        let stdout = std::io::stdout();
-        let mut stdout = stdout.lock();
-        AlertMessage::alert(&mut stdout, format!("{}", entries.unwrap_err())).ok();
+        let stderr = std::io::stderr();
+        let mut stderr = stderr.lock();
+        AlertMessage::alert(&mut stderr, format!("{}", entries.unwrap_err())).ok();
         return vec![];
     }
 
@@ -93,12 +93,10 @@ fn collect_evtxfiles(dirpath: &str) -> Vec<PathBuf> {
 }
 
 fn print_credits() {
-    let stdout = std::io::stdout();
-    let mut stdout = stdout.lock();
     match fs::read_to_string("./credits.txt") {
         Ok(contents) => println!("{}", contents),
         Err(err) => {
-            AlertMessage::alert(&mut stdout, format!("{}", err)).ok();
+            AlertMessage::alert(&mut std::io::stderr().lock(), format!("{}", err)).ok();
         }
     }
 }
@@ -153,7 +151,7 @@ fn analysis_file(
                     evtx_filepath,
                     record_result.unwrap_err()
                 );
-                AlertMessage::alert(&mut std::io::stdout().lock(), errmsg).ok();
+                AlertMessage::alert(&mut std::io::stderr().lock(), errmsg).ok();
                 continue;
             }
 
diff --git a/src/yaml.rs b/src/yaml.rs
index 700933fa..cdf14268 100644
--- a/src/yaml.rs
+++ b/src/yaml.rs
@@ -34,8 +34,6 @@ impl ParseYaml {
     }
 
     pub fn read_dir<P: AsRef<Path>>(&mut self, path: P, level: &str) -> io::Result<String> {
-        let stdout = std::io::stdout();
-        let mut stdout = stdout.lock();
         let mut entries = fs::read_dir(path)?;
         let yaml_docs = entries.try_fold(vec![], |mut ret, entry| {
             let entry = entry?;
@@ -59,7 +57,7 @@ impl ParseYaml {
             let read_content = self.read_file(path);
             if read_content.is_err() {
                 AlertMessage::alert(
-                    &mut stdout,
+                    &mut std::io::stderr().lock(),
                     format!(
                         "fail to read file: {}\n{} ",
                         entry.path().display(),
@@ -73,7 +71,7 @@ impl ParseYaml {
             let yaml_contents = YamlLoader::load_from_str(&read_content.unwrap());
             if yaml_contents.is_err() {
                 AlertMessage::alert(
-                    &mut stdout,
+                    &mut std::io::stderr().lock(),
                     format!(
                         "fail to parse as yaml: {}\n{} ",
                         entry.path().display(),