diff --git a/cpp/src/arrow/util/align_util.cc b/cpp/src/arrow/util/align_util.cc
index ac2d485af8c9d..ef224ebbd9255 100644
--- a/cpp/src/arrow/util/align_util.cc
+++ b/cpp/src/arrow/util/align_util.cc
@@ -49,7 +49,7 @@ Type::type GetTypeForBuffers(const ArrayData& array) {
   if (type_id == Type::DICTIONARY) {
     // return index type id, provided by the DictionaryType array.type or
     // array.type->storage_type() if array.type is an ExtensionType
-    const std::shared_ptr<DataType>& dict_type = array.type;
+    std::shared_ptr<DataType> dict_type = array.type;
     if (array.type->id() == Type::EXTENSION) {
       dict_type = checked_pointer_cast<ExtensionType>(array.type)->storage_type();
     }