A recording and reproducing apparatus for a photosensitive recording medium, the apparatus comprising: a case as defined herein; an loading slot shutter as defined herein; an unlocking mechanism as defined herein; and a shutter opening mechanism as defined herein, wherein the unlocking mechanism starts the unlocking of the second locking member immediately after a leading end of the photosensitive recording medium cartridge is inserted into the loading slot and starts the unlocking of the first locking member immediately after the second locking member is unlocked, and the shutter opening mechanism opens the shutter of the photosensitive recording medium cartridge when the photosensitive recording medium cartridge reaches a predetermined position.