An information processing device may include a first frame provided with a scanner for reading information recorded on a medium, a second frame which faces the first frame across a traveling path and is provided with a pressing member for pressing the medium toward a reading face of the scanner, a support plate which supports the pressing member and whose one end is axially supported with the second frame to be movable between a locked position where the pressing member is protruded in the traveling path and an open position where a reading face of the scanner is exposed, a locking part for locking the support plate to the second frame at the locked position, and a half lock preventing mechanism for preventing a half-lock state when the support plate is locked to the second frame.