diff --git a/README.md b/README.md
index e3302d5..261f68f 100644
--- a/README.md
+++ b/README.md
@@ -69,7 +69,7 @@ using System.Runtime.InteropServices;
 
 namespace CsBindgen
 {
-    public static unsafe partial class NativeMethods
+    internal static unsafe partial class NativeMethods
     {
         const string __DllName = "liblz4";
 
@@ -126,7 +126,7 @@ using System.Runtime.InteropServices;
 
 namespace CsBindgen
 {
-    public static unsafe partial class NativeMethods
+    internal static unsafe partial class NativeMethods
     {
         const string __DllName = "nativelib";
 
@@ -148,6 +148,7 @@ csbindgen::Builder::default()
     .rust_file_header("use super::lz4;")
     .rust_method_type_path("lz4")
     .csharp_class_name("LibLz4")
+    .csharp_class_accessibility("public")
     .csharp_namespace("CsBindgen")
     .csharp_dll_name("csbindgen_tests")
     .csharp_dll_name_if("UNITY_IOS && !UNITY_EDITOR", "__Internal")
@@ -182,7 +183,7 @@ using System.Runtime.InteropServices;
 
 namespace {csharp_namespace}
 {
-    public static unsafe partial class {csharp_class_name}
+    {csharp_class_accessibility} static unsafe partial class {csharp_class_name}
     {
 #if {csharp_dll_name_if(if_symbol,...)}
         const string __DllName = "{csharp_dll_name_if(...,if_dll_name)}";
@@ -207,7 +208,7 @@ Adjust `rust_file_header` and `rust_method_type_path` to match your module confi
 If the file path to be loaded needs to be changed depending on the operating system, the following load code can be used.
 
 ```csharp
-public static unsafe partial class NativeMethods
+internal static unsafe partial class NativeMethods
 {
     // https://docs.microsoft.com/en-us/dotnet/standard/native-interop/cross-platform
     // Library path will search
diff --git a/csbindgen-tests/build.rs b/csbindgen-tests/build.rs
index 708ed4c..3144313 100644
--- a/csbindgen-tests/build.rs
+++ b/csbindgen-tests/build.rs
@@ -52,6 +52,7 @@ fn main() {
         .csharp_dll_name_if("UNITY_IOS && !UNITY_EDITOR", "__Internal")
         .csharp_entry_point_prefix("csbindgen_")
         .csharp_method_prefix("")
+        .csharp_class_accessibility("public")
         .csharp_c_long_convert("int")
         .csharp_c_ulong_convert("uint")
         .generate_to_file("src/lz4_ffi.rs", "../dotnet-sandbox/lz4_bindgen.cs")
diff --git a/csbindgen/Cargo.toml b/csbindgen/Cargo.toml
index 0472631..6bb74f6 100644
--- a/csbindgen/Cargo.toml
+++ b/csbindgen/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "csbindgen"
-version = "0.1.1"
+version = "0.1.2"
 edition = "2021"
 authors = [
   "Yoshifumi Kawai <ils@neue.cc>",
diff --git a/csbindgen/src/builder.rs b/csbindgen/src/builder.rs
index e0b5c78..a22f61b 100644
--- a/csbindgen/src/builder.rs
+++ b/csbindgen/src/builder.rs
@@ -21,6 +21,7 @@ pub struct BindgenOptions {
     pub csharp_namespace: String,
     pub csharp_class_name: String,
     pub csharp_dll_name: String,
+    pub csharp_class_accessibility: String,
     pub csharp_entry_point_prefix: String,
     pub csharp_method_prefix: String,
     pub csharp_c_long_convert: String,
@@ -44,6 +45,7 @@ impl Default for Builder {
                 csharp_dll_name: "".to_string(),
                 csharp_entry_point_prefix: "".to_string(),
                 csharp_method_prefix: "".to_string(),
+                csharp_class_accessibility: "internal".to_string(),
                 csharp_c_long_convert: "int".to_string(),
                 csharp_c_ulong_convert: "uint".to_string(),
                 csharp_if_symbol: "".to_string(),
@@ -135,6 +137,13 @@ impl Builder {
         self
     }
 
+    /// configure C# class accessibility, default is internal
+    /// `{csharp_class_accessibility} static unsafe partial class NativeMethods`
+    pub fn csharp_class_accessibility<T: Into<String>>(mut self, csharp_class_accessibility: T) -> Builder {
+        self.options.csharp_class_accessibility = csharp_class_accessibility.into();
+        self
+    }
+
     /// configure c_long to {csharp_c_long_convert} type,
     /// default is `int`.
     pub fn csharp_c_long_convert<T: Into<String>>(mut self, csharp_c_long_convert: T) -> Builder {
diff --git a/csbindgen/src/emitter.rs b/csbindgen/src/emitter.rs
index aa2402f..8c7af83 100644
--- a/csbindgen/src/emitter.rs
+++ b/csbindgen/src/emitter.rs
@@ -87,6 +87,7 @@ pub fn emit_csharp(
     let namespace = &options.csharp_namespace;
     let class_name = &options.csharp_class_name;
     let method_prefix = &options.csharp_method_prefix;
+    let accessibility = &options.csharp_class_accessibility;
 
     let dll_name = match options.csharp_if_symbol.as_str() {
         "" => format!("        const string __DllName = \"{}\";", options.csharp_dll_name),
@@ -176,7 +177,7 @@ using System.Runtime.InteropServices;
 
 namespace {namespace}
 {{
-    public static unsafe partial class {class_name}
+    {accessibility} static unsafe partial class {class_name}
     {{
 {dll_name}
 
diff --git a/dotnet-sandbox/Program.cs b/dotnet-sandbox/Program.cs
index 2aee533..4f681ab 100644
--- a/dotnet-sandbox/Program.cs
+++ b/dotnet-sandbox/Program.cs
@@ -11,7 +11,7 @@ unsafe
     var z = LibRust.my_add(100, 200);
     Console.WriteLine(z);
 
-    var s = LibLz4.LZ4_versionString();
+    var s = CsBindgen.LibLz4.LZ4_versionString();
     var ss = new string((sbyte*)s);
     Console.WriteLine(ss);
 
@@ -33,7 +33,6 @@ unsafe
 
 }
 
-namespace CsBindgen
 {
     public static unsafe partial class LibLz4
     {
diff --git a/dotnet-sandbox/method_call.cs b/dotnet-sandbox/method_call.cs
index bb535a6..af21cb2 100644
--- a/dotnet-sandbox/method_call.cs
+++ b/dotnet-sandbox/method_call.cs
@@ -7,7 +7,7 @@ using System.Runtime.InteropServices;
 
 namespace CsBindgen
 {
-    public static unsafe partial class LibRust
+    internal static unsafe partial class LibRust
     {
         const string __DllName = "csbindgen_tests";