A combined storage apparatus comprises a storage bag and a storage box. The bottom of the storage bag forms an extended flat surface and is attached with a stiff board. Two sides of the stiff board are provided with locking members. Thereby, after the storage bag contains an article and is vacuumed, two lateral sections of the stiff board are folded upward to form two sidewalls. The storage bag is then placed into the storage box. Since the combined storage apparatus is boxy and of tough structure, a plurality of them can be stacked up so as to save storage space.