A recording and/or reproduction apparatus includes a chassis, a recording and/or reproduction device provided on the chassis so as to perform recording and/or reproduction on a disk cartridge, a cartridge holder for holding the disk cartridge, the cartridge holder being supported to be movable between a disk cartridge insertion/draw-out position and a recording/reproduction position relative to the chassis, an eject lever provided to be movable in the direction for insertion and draw-out of the disk cartridge relative to the chassis, a biasing device for biasing the eject lever in a disk cartridge discharging direction, a shutter unlocking member mounted to one side surface of the cartridge holder, and a shutter unlocking member movement restriction portion provided on the chassis and operable to restrict the shutter lock unlocking member from moving in the direction of spacing away from the one side surface when the cartridge holder is located in the recording/reproduction position.