diff --git a/PrimePickApp/MainView.swift b/PrimePickApp/MainView.swift
index 42c6629..f1ffc3c 100644
--- a/PrimePickApp/MainView.swift
+++ b/PrimePickApp/MainView.swift
@@ -8,6 +8,8 @@
 import SwiftUI
 
 struct MainView: View {
+    @State private var hue: Double = 0
+    
     var body: some View {
         NavigationStack {
             ZStack {
@@ -15,11 +17,35 @@ struct MainView: View {
                     .ignoresSafeArea()
                 
                 VStack {
-                    Text("PrimePick")
-                        .font(.custom("Helvetica Neue", size: 40))
+                    Spacer()
+                    
+                    Text("Prime Pick")
+                        .font(.custom("Helvetica Neue", size: 60))
+                        .foregroundStyle(.black)
                         .fontWeight(.bold)
-                        .padding(.top, 100)
-                        .padding(.bottom, 30)
+                        .offset(x: 2, y: 2)
+                        .foregroundColor(Color.white) // 文字自体を白に設定
+                        .overlay(
+                            LinearGradient(
+                                gradient: Gradient(colors: [
+                                    Color.red, Color.orange, Color.yellow, Color.green,
+                                    Color.blue, Color.purple, Color.red
+                                ]),
+                                startPoint: .leading,
+                                endPoint: .trailing
+                            )
+                            .mask(
+                                Text("Prime Pick")
+                                    .font(.custom("Helvetica Neue", size: 60))
+                                    .fontWeight(.bold)
+                            )
+                            .hueRotation(Angle(degrees: hue))
+                        )
+                        .onAppear {
+                            withAnimation(Animation.linear(duration: 1).repeatForever(autoreverses: false)) {
+                                hue = 360
+                            }
+                        }
                     
                     Spacer()
                     
@@ -105,6 +131,21 @@ struct LazyView<Content: View>: View {
    }
 }
 
+struct RainbowTextModifier: AnimatableModifier {
+    var hue: Double
+
+    var animatableData: Double {
+        get { hue }
+        set { hue = newValue }
+    }
+
+    func body(content: Content) -> some View {
+        content
+            .foregroundColor(Color(hue: hue, saturation: 1, brightness: 1))
+            .animation(Animation.linear(duration: 2).repeatForever(autoreverses: false))
+    }
+}
+
 #Preview {
     MainView()
 }