A wall body attachment unit (1) is secured by screws (2) to a wall body (W), a shelf board support unit (4) is removably attached to the wall body attachment unit (1) by engaging a curved engagement portion (4a) into a corresponding engaged portion of the wall body attachment unit (1). The shelf board support unit (4) holds a shelf board between a shelf board holding board portion (4b) and a shelf board holding lower board portion (4e) while a distance between the upper and lower members (4A) and (4B), which are secured to each other. Thus, the shelf board (3) can be supported by the shelf board support unit (4) at a low position on the ground, but not at an attachment position on the wall body.