To fix an apparatus to an apparatus supporting device and to detach it from the device by a simple operation.

After hooking a part to be engaged of the apparatus A to a second hook member 5 projected from a loading surface 3a, a first hook member 4 is moved and engaged with the apparatus A. Then, when the first hook member 4 is locked by a lock operation part 62 and a lock part 61, the apparatus A is fixed to the loading surface 3a by the hook members 4 and 5. Also, when the lock operation part 62 is operated and the lock of the lock part 61 is released, the apparatus A is detached from the loading surface 3a.