diff --git a/.gitignore b/.gitignore
index 959b2c8..4abbde2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -33,4 +33,6 @@ data/
 venv/
 .venv/
 
+logs/
+
 site/
\ No newline at end of file
diff --git a/cmd/splashscreen-changer/args.go b/cmd/splashscreen-changer/args.go
index 49b3636..d370708 100644
--- a/cmd/splashscreen-changer/args.go
+++ b/cmd/splashscreen-changer/args.go
@@ -37,6 +37,7 @@ func printHelp() {
 
 	fmt.Println()
 	fmt.Println("GitHub: https://github.com/tomacheese/splashscreen-changer")
+	fmt.Println("Booth: https://tomachi.booth.pm/items/6284870")
 }
 
 func getSourcePath(config *Config) (string, error) {
diff --git a/cmd/splashscreen-changer/config.go b/cmd/splashscreen-changer/config.go
index 7ac47b8..94ee262 100644
--- a/cmd/splashscreen-changer/config.go
+++ b/cmd/splashscreen-changer/config.go
@@ -20,6 +20,9 @@ type Config struct {
 		Width  int    `yaml:"width" help:"Width of the destination image" default:"800"`
 		Height int    `yaml:"height" help:"Height of the destination image" default:"450"`
 	} `yaml:"destination" required:"true"`
+	Log struct {
+		Path string `yaml:"path" help:"Path to the log file" default:""`
+	} `yaml:"log"`
 }
 
 // 設定ファイルを読み込む
diff --git a/cmd/splashscreen-changer/log.go b/cmd/splashscreen-changer/log.go
new file mode 100644
index 0000000..78670f0
--- /dev/null
+++ b/cmd/splashscreen-changer/log.go
@@ -0,0 +1,30 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"time"
+)
+
+func getLogFilePath(logParamPath *string) string {
+	// ログフォルダパスは環境変数 LOG_PATH または引数 -log で指定し、指定されていない場合は "logs/" とする。
+	// "logs/" の場所は、実行ファイルと同じディレクトリにあるものとする。go runで実行する場合は、カレントディレクトリにあるものとする。
+	// ログファイルのファイル名は、yyyy-mm-dd.log とする。
+	if *logParamPath != "" {
+		return *logParamPath
+	}
+
+	date := time.Now().Format("2006-01-02")
+
+	exePath, err := os.Executable()
+	if err != nil {
+		return filepath.Join("logs", date+".log")
+	}
+
+	if isGoRun() {
+		return filepath.Join("logs", date+".log")
+	}
+
+	exeDir := filepath.Dir(exePath)
+	return filepath.Join(exeDir, "logs", date+".log")
+}
diff --git a/cmd/splashscreen-changer/main.go b/cmd/splashscreen-changer/main.go
index d3f6ac2..146ecf3 100644
--- a/cmd/splashscreen-changer/main.go
+++ b/cmd/splashscreen-changer/main.go
@@ -5,6 +5,8 @@ import (
 	"fmt"
 	"image"
 	"image/png"
+	"io"
+	"log"
 	"os"
 	"path/filepath"
 	"strings"
@@ -184,81 +186,96 @@ func main() {
 
 	// バージョン情報を表示する
 	if *versionFlag {
-		fmt.Println("splashscreen-changer")
-		fmt.Println("|- Version", GetAppVersion())
-		fmt.Println("|- Build date:", GetAppDate())
+		log.Println("splashscreen-changer")
+		log.Println("|- Version", GetAppVersion())
+		log.Println("|- Build date:", GetAppDate())
 		return
 	}
 
 	// 設定ファイルを読み込む。
 	configPath := getConfigPath(configParamPath)
 
-	fmt.Println("Loading config file:", configPath)
+	log.Println("Loading config file:", configPath)
 	config, err := LoadConfig(configPath)
 	if err != nil {
-		fmt.Println("Failed to load configuration file:", err)
+		log.Println("Failed to load configuration file:", err)
 		return
 	}
 
+	// ログファイルを開く
+	path := getLogFilePath(&config.Log.Path)
+	// ログファイルの親ディレクトリが存在しない場合は作成する
+	if err := os.MkdirAll(filepath.Dir(path), os.ModePerm); err != nil {
+		log.Fatal(err)
+	}
+	file, err := os.OpenFile(path, os.O_CREATE|os.O_APPEND|os.O_RDWR, 0644)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	defer file.Close()
+	mw := io.MultiWriter(os.Stdout, file)
+	log.SetOutput(mw)
+
 	sourcePath, err := getSourcePath(config)
 	if err != nil {
-		fmt.Println("Failed to obtain source path")
-		fmt.Println()
-		fmt.Println("The following steps are used to obtain the source paths. This error occurs because the following steps could not be taken to obtain the source path.")
-		fmt.Println("1. Environment variable SOURCE_PATH. If this is not set, the following steps are taken.")
-		fmt.Println("2. source.path in Configuration file. If this is not set, the following steps are taken.")
-		fmt.Println("3. Check if the VRChat folder exists in the Pictures folder in the user folder.")
-		fmt.Println("If the VRChat folder exists, the path to the VRChat folder is used as the source path.")
+		log.Println("Failed to obtain source path")
+		log.Println()
+		log.Println("The following steps are used to obtain the source paths. This error occurs because the following steps could not be taken to obtain the source path.")
+		log.Println("1. Environment variable SOURCE_PATH. If this is not set, the following steps are taken.")
+		log.Println("2. source.path in Configuration file. If this is not set, the following steps are taken.")
+		log.Println("3. Check if the VRChat folder exists in the Pictures folder in the user folder.")
+		log.Println("If the VRChat folder exists, the path to the VRChat folder is used as the source path.")
 		return
 	}
 
 	destinationPath, err := getDestinationPath(config)
 	if err != nil {
-		fmt.Println("Failed to obtain destination path")
-		fmt.Println()
-		fmt.Println("The following steps are used to obtain the destination paths. This error occurs because the following steps could not be taken to obtain the destination path.")
-		fmt.Println("1. Environment variable DESTINATION_PATH. If this is not set, the following steps are taken.")
-		fmt.Println("2. destination.path in Configuration file. If this is not set, the following steps are taken.")
-		fmt.Println("3. Get the installation destination folder of VRChat from the Steam library folder.")
-		fmt.Println("If the EasyAntiCheat folder exists in the VRChat folder, the path to the VRChat folder is used as the destination path.")
+		log.Println("Failed to obtain destination path")
+		log.Println()
+		log.Println("The following steps are used to obtain the destination paths. This error occurs because the following steps could not be taken to obtain the destination path.")
+		log.Println("1. Environment variable DESTINATION_PATH. If this is not set, the following steps are taken.")
+		log.Println("2. destination.path in Configuration file. If this is not set, the following steps are taken.")
+		log.Println("3. Get the installation destination folder of VRChat from the Steam library folder.")
+		log.Println("If the EasyAntiCheat folder exists in the VRChat folder, the path to the VRChat folder is used as the destination path.")
 		return
 	}
 
 	// 設定値を表示する
-	fmt.Printf("Source Path: %s\n", sourcePath)
-	fmt.Printf("Source Recursive: %t\n", config.Source.Recursive)
-	fmt.Printf("Destination Path: %s\n", destinationPath)
-	fmt.Printf("Destination Width: %d\n", config.Destination.Width)
-	fmt.Printf("Destination Height: %d\n", config.Destination.Height)
+	log.Printf("Source Path: %s\n", sourcePath)
+	log.Printf("Source Recursive: %t\n", config.Source.Recursive)
+	log.Printf("Destination Path: %s\n", destinationPath)
+	log.Printf("Destination Width: %d\n", config.Destination.Width)
+	log.Printf("Destination Height: %d\n", config.Destination.Height)
 
 	// ソースディレクトリ以下のPNGファイルをリストする
 	files, err := listPNGFiles(sourcePath, config.Source.Recursive)
 	if err != nil {
-		fmt.Println("Error:", err)
+		log.Println("Error:", err)
 		return
 	}
 
 	// ランダムで1つのファイルを選択する
 	if len(files) == 0 {
-		fmt.Println("No PNG files found")
+		log.Println("No PNG files found")
 		return
 	}
 
 	pickedFile, err := pickRandomFile(files)
 	if err != nil {
-		fmt.Println("Error:", err)
+		log.Println("Error:", err)
 		return
 	}
 
-	fmt.Println("Picked file:", pickedFile)
+	log.Println("Picked file:", pickedFile)
 
 	// ファイルをリサイズして EasyAntiCheat ディレクトリに保存する
 	destFile := filepath.Join(destinationPath, "EasyAntiCheat", "SplashScreen.png")
 	err = resizePNGFile(pickedFile, destFile, config.Destination.Width, config.Destination.Height)
 	if err != nil {
-		fmt.Println("Error:", err)
+		log.Println("Error:", err)
 		return
 	}
 
-	fmt.Println("Resized file saved to:", destFile)
+	log.Println("Resized file saved to:", destFile)
 }
diff --git a/docs/settings/file.md b/docs/settings/file.md
index d0f40c2..be99db4 100644
--- a/docs/settings/file.md
+++ b/docs/settings/file.md
@@ -102,6 +102,16 @@
 
 この設定項目の値と、`destination.width` の値から、選択された画像を自動的にクロップ・リサイズします。具体的な挙動については、後述する「クロップ・リサイズの仕様」をご覧ください。
 
+### log.path
+
+| 必須か | デフォルト値 | 環境変数 |
+| :- | :- | :- |
+| いいえ | `logs/` | `LOG_PATH` |
+
+ログファイルの出力先フォルダパスを指定します。
+
+指定しない場合、実行ファイルと同じ階層の `logs` フォルダに `yyyy-MM-dd.log` 形式で出力します。
+
 ## クロップ・リサイズの仕様
 
 選択された画像は、設定ファイルで指定された `destination.width` と `destination.height` の値に基づき、自動的にクロップおよびリサイズされます。