To provide a storage unit which can be assembled easily and of which constitution members do not take much space when being transported, and utilize a wall surface which comes behind the storage unit as a back board.

The storage unit utilizing wall surface A is placed to make its back side in contact with a wall surface of a building, and the open back side is closed by the wall surface because of no back boards. The storage unit A has a top plate 1 placed on the top, a bottom part 2 placed on the bottom, side parts 3 placed on the both sides, doors 4b placed on the front of a space surrounded by the top plate 1, the bottom part 2, and side parts 3 on the right and left, and an opening and closing frame 4 with a rectangular frame 4a supporting the doors 4b. The top plate 1, bottom part 2, side parts 3, and the opening and closing frame 4 are carried into the building and are assembled with the back side of the storage unit in contact with the wall surface.