A roll medium supporting apparatus includes: a base body portion to be inserted into a hollow shaft portion of a rolled medium; a plurality of contact supporting portions provided circumferentially of the base body portion so as to be capable of being displaced radially of the hollow shaft portion, having a plurality of predetermined positions within the displaceable range, and coming into contact with the inner peripheral surface of the hollow shaft portion and supporting the same; and a stabilizing mechanism configured to stabilize the contact supporting portions at the plurality of predetermined positions.