The cartridge includes a box with a receptacle for receiving a disc, a central hole for receiving a rotatable member for rotating the disc and a head slit. A channel-sectioned shutter is movably mounted on the outer surface of the box for closing the hole and slit and a slider is provided for moving the shutter to open and close the hold and slit. The slider is movably guided in a groove and an elastic member resiliently biases the shutter in a direction in which the hole and slit are normally closed. The receptacle has an inner wall concentric with the hole and is cylindrically shaped to completely surround the entire outer periperhy of the disc thereby preventing the disc from being exposed to the outside except through the hole and slit when the shutter is opened.
