An objective of the present invention is to allow avoiding damage to a device or medium when carrying out maintenance work. A temporary retaining part has on the outside of the left side surface thereof an exposed manipulable knob for rotating a drum, and a knob cover is disposed on the outside of the knob. In the temporary retaining part, when an open guide is in a closed state and the upper side of the drum is closed, the knob cover is set into a covering state by way of a stud so as to restrict manipulation of the manipulable knob and thereby prevent paper currency jamming from worsening further in advance. In addition, in the temporary retaining part, when the open guide is rotated from the closed state toward an opening direction so as to expose the upper side of the drum, the knob cover rotates to an exposure direction due to the action of a spring and is set into an exposure state, allowing for manual rotation of the drum by the manipulation of the manipulable knob with an escape path being ensured for torn paper currency.