Disk device with insertion slot capable of preventing double loading of disks

A disk device for writing and/or reading data in a disk in a casing, comprising:

• an insertion slot formed in said casing;
• a loading mechanism for loading said disk in said casing or unloading said disk from said casing through said insertion slot;
• a shutter shiftable between a closed position and an open position, for closing said insertion slot at least partially to prevent said disk from passing when in said closed position, and for opening said insertion slot to allow said disk to pass when in said open position;
• a shift lever, disposed for connection between said loading mechanism and said shutter, for moving said shutter in a first direction along an elongate slot shape of said insertion slot upon passage of said disk through said insertion slot according to operation for loading said disk, and for moving said shutter in a second direction reverse to said first direction before passage of said disk through said insertion slot according to operation for unloading said disk;
• a cam mechanism, including a cam surface and a cam follower projection, said cam surface being formed with one of said shutter and a stationary plate portion of said casing, said cam follower projection being formed with a remaining one of said shutter and said stationary plate portion, said cam mechanism shifting said shutter to said closed position when said shutter moves in said first direction, and shifting said shutter to said open position when said shutter moves in said second direction.