An image forming apparatus set (200) includes an image forming apparatus (100) and a mounting base (3) on which the image forming apparatus (100) is placed. The mounting base (3) includes a locking mechanism (R). When the image forming apparatus (100) is placed at a first position in the mounting base (3), the locking mechanism (R) restricts movement of the image forming apparatus (100) relative to the mounting base (3). The locking mechanism (R) includes a first locking mechanism (4) and a second locking mechanism (R2). The first locking mechanism (4) restricts movement of the image forming apparatus (100) in a first direction (D1) relative to the mounting base (3). The second locking mechanism (R2) restricts movement of the image forming apparatus (100) in a second direction (D2) relative to the mounting base (3). The second direction (D2) is opposite to the first direction (D1).