diff --git a/Example1/AudioMessage.cs b/Example1/AudioMessage.cs
deleted file mode 100644
index 20793d7b..00000000
--- a/Example1/AudioMessage.cs
+++ /dev/null
@@ -1,12 +0,0 @@
-using System;
-
-namespace Example1
-{
-  internal class AudioMessage
-  {
-    public uint     user_id;
-    public byte     ch_num;
-    public uint     buffer_length;
-    public float[,] buffer_array;
-  }
-}
diff --git a/Example1/Example1.csproj b/Example1/Example1.csproj
index 1e3425ae..81c52eff 100644
--- a/Example1/Example1.csproj
+++ b/Example1/Example1.csproj
@@ -62,7 +62,6 @@
     <Compile Include="AssemblyInfo.cs" />
     <Compile Include="AudioStreamer.cs" />
     <Compile Include="Program.cs" />
-    <Compile Include="AudioMessage.cs" />
     <Compile Include="TextMessage.cs" />
     <Compile Include="NotificationMessage.cs" />
     <Compile Include="Notifier.cs" />