To prevent double loading of recording media into a recording/ reproducing device.

A panel 1 is formed with an inserting hole 3 for inserting the recording medium 2 to be freely insertible and ejectable, and a carrier device 6 of the recording medium 2 is arranged in the rear of the panel 1. A shutter 13 is arranged in the rear of the panel 1 to be movable freely and approximately parallel to the panel 1, and the shutter 13 is capable of changing its position between an opening position for opening the inserting hole 3 and a closing position for closing the inserting hole 3, and also the shutter 13 is energized to the side of the opening position, and an operating member 14 is arranged in the rear of the panel 1. At the time of carrying the recording medium 2 into a recording/reproducing position by the carrier device 6, the opening member 14 is pressed by the recording medium 2 to move the shutter 13 into the closing position.