diff --git a/cpp/src/arrow/array/array_nested.cc b/cpp/src/arrow/array/array_nested.cc
index fb2efe9ae50c3..1053153d88bf5 100644
--- a/cpp/src/arrow/array/array_nested.cc
+++ b/cpp/src/arrow/array/array_nested.cc
@@ -807,7 +807,7 @@ MapArray::MapArray(const std::shared_ptr<DataType>& type, int64_t length,
 Result<std::shared_ptr<Array>> MapArray::FromArraysInternal(
     std::shared_ptr<DataType> type, const std::shared_ptr<Array>& offsets,
     const std::shared_ptr<Array>& keys, const std::shared_ptr<Array>& items,
-    MemoryPool* pool, const std::shared_ptr<Buffer>& null_bitmap) {
+    MemoryPool* pool, std::shared_ptr<Buffer> null_bitmap) {
   using offset_type = typename MapType::offset_type;
   using OffsetArrowType = typename CTypeTraits<offset_type>::ArrowType;
 
@@ -861,7 +861,7 @@ Result<std::shared_ptr<Array>> MapArray::FromArraysInternal(
 Result<std::shared_ptr<Array>> MapArray::FromArrays(
     const std::shared_ptr<Array>& offsets, const std::shared_ptr<Array>& keys,
     const std::shared_ptr<Array>& items, MemoryPool* pool,
-    const std::shared_ptr<Buffer>& null_bitmap) {
+    std::shared_ptr<Buffer> null_bitmap) {
   return FromArraysInternal(std::make_shared<MapType>(keys->type(), items->type()),
                             offsets, keys, items, pool, null_bitmap);
 }
@@ -869,7 +869,7 @@ Result<std::shared_ptr<Array>> MapArray::FromArrays(
 Result<std::shared_ptr<Array>> MapArray::FromArrays(
     std::shared_ptr<DataType> type, const std::shared_ptr<Array>& offsets,
     const std::shared_ptr<Array>& keys, const std::shared_ptr<Array>& items,
-    MemoryPool* pool, const std::shared_ptr<Buffer>& null_bitmap) {
+    MemoryPool* pool, std::shared_ptr<Buffer> null_bitmap) {
   if (type->id() != Type::MAP) {
     return Status::TypeError("Expected map type, got ", type->ToString());
   }
diff --git a/cpp/src/arrow/array/array_nested.h b/cpp/src/arrow/array/array_nested.h
index f96b6bd3b1346..a6d4977839ef1 100644
--- a/cpp/src/arrow/array/array_nested.h
+++ b/cpp/src/arrow/array/array_nested.h
@@ -537,13 +537,13 @@ class ARROW_EXPORT MapArray : public ListArray {
   static Result<std::shared_ptr<Array>> FromArrays(
       const std::shared_ptr<Array>& offsets, const std::shared_ptr<Array>& keys,
       const std::shared_ptr<Array>& items, MemoryPool* pool = default_memory_pool(),
-      const std::shared_ptr<Buffer>& null_bitmap = NULLPTR);
+      std::shared_ptr<Buffer> null_bitmap = NULLPTR);
 
   static Result<std::shared_ptr<Array>> FromArrays(
       std::shared_ptr<DataType> type, const std::shared_ptr<Array>& offsets,
       const std::shared_ptr<Array>& keys, const std::shared_ptr<Array>& items,
       MemoryPool* pool = default_memory_pool(),
-      const std::shared_ptr<Buffer>& null_bitmap = NULLPTR);
+      std::shared_ptr<Buffer> null_bitmap = NULLPTR);
 
   const MapType* map_type() const { return map_type_; }
 
@@ -563,7 +563,7 @@ class ARROW_EXPORT MapArray : public ListArray {
   static Result<std::shared_ptr<Array>> FromArraysInternal(
       std::shared_ptr<DataType> type, const std::shared_ptr<Array>& offsets,
       const std::shared_ptr<Array>& keys, const std::shared_ptr<Array>& items,
-      MemoryPool* pool, const std::shared_ptr<Buffer>& null_bitmap = NULLPTR);
+      MemoryPool* pool, std::shared_ptr<Buffer> null_bitmap = NULLPTR);
 
  private:
   const MapType* map_type_;