diff --git a/src/python.ts b/src/python.ts
index 4f75089..77c67f2 100644
--- a/src/python.ts
+++ b/src/python.ts
@@ -495,10 +495,12 @@ export class PyObject {
       case "symbol":
       case "string": {
         const str = String(v);
+        const encoder = new TextEncoder();
+        const u8 = encoder.encode(str);
         return new PyObject(
           py.PyUnicode_DecodeUTF8(
-            cstr(str),
-            str.length,
+            u8,
+            u8.byteLength,
             null,
           ),
         );
diff --git a/test/test.ts b/test/test.ts
index 99ce34a..af063a5 100644
--- a/test/test.ts
+++ b/test/test.ts
@@ -35,6 +35,9 @@ Deno.test("types", async (t) => {
   await t.step("str", () => {
     const value = python.str("hello");
     assertEquals(value.valueOf(), "hello");
+
+    const unicode = python.str("'中文'");
+    assertEquals(unicode.valueOf(), "'中文'");
   });
 
   await t.step("list", () => {