A stopping mechanism is disposed on a machine body and a removable device. The stopping mechanism includes a rectilinearly moving action member, a rotationally moving clipping member, and a stopping member fixedly disposed on the machine body, in which the action member pushes and presses against the clipping member so that the clipping member rotates to a holder position. The action member presses against the stopping member fixedly disposed on the machine body through a tilt angle relation at the holder position, so that an accelerating force generated by the removable device under impact is transferred to the machine body, thus dispersing the impact force.