diff --git a/src/hwpx/opc/package.py b/src/hwpx/opc/package.py
index 05d3e55..25cad43 100644
--- a/src/hwpx/opc/package.py
+++ b/src/hwpx/opc/package.py
@@ -490,16 +490,25 @@ def _save_to_zip(self, pkg_file: str | Path | BinaryIO) -> None:
             self._version.mark_clean()
         self._validate_structure()
         with ZipFile(pkg_file, "w") as zf:
-            self._write_mimetype(zf)
-            for name in sorted(self._files):
-                if name == self.MIMETYPE_PATH:
-                    continue
-                data = self._files[name]
-                info = ZipInfo(name)
-                info.compress_type = ZIP_DEFLATED
-                zf.writestr(info, data)
+            self._write_archive(zf)
+
+    def _write_archive(self, zf: ZipFile) -> None:
+        self._write_mimetype(zf)
+        for name in sorted(self._files):
+            if name == self.MIMETYPE_PATH:
+                continue
+            self._write_zip_entry(zf, name, self._files[name], ZIP_DEFLATED)
+
+    @staticmethod
+    def _write_zip_entry(zf: ZipFile, path: str, payload: bytes, compress_type: int) -> None:
+        info = ZipInfo(path)
+        info.compress_type = compress_type
+        zf.writestr(info, payload)
 
     def _write_mimetype(self, zf: ZipFile) -> None:
-        info = ZipInfo(self.MIMETYPE_PATH)
-        info.compress_type = ZIP_STORED
-        zf.writestr(info, self._files[self.MIMETYPE_PATH])
+        self._write_zip_entry(
+            zf,
+            self.MIMETYPE_PATH,
+            self._files[self.MIMETYPE_PATH],
+            ZIP_STORED,
+        )
diff --git a/tests/test_opc_package.py b/tests/test_opc_package.py
index b1ccdbc..6425166 100644
--- a/tests/test_opc_package.py
+++ b/tests/test_opc_package.py
@@ -66,3 +66,16 @@ def test_missing_required_files_raise_structure_error() -> None:
 
     with pytest.raises(HwpxStructureError):
         HwpxPackage.open(_build_package(include_version=False))
+
+
+def test_save_preserves_expected_compress_type_per_entry() -> None:
+    package = HwpxPackage.open(_build_package())
+
+    output = package.save()
+    with ZipFile(io.BytesIO(output), "r") as archive:
+        infos = archive.infolist()
+
+    assert infos[0].filename == "mimetype"
+    assert infos[0].compress_type == ZIP_STORED
+    for info in infos[1:]:
+        assert info.compress_type == ZIP_DEFLATED