PURPOSE: To keep the jumping quantity of a cartridge outside a device at a constant quantity, and to surely prevent the cartridge from being dropped, by providing a jumping quantity regulating lever having a claw part, and pressed by a spring, on a cartridge holder, in such a way that it can turn freely.

CONSTITUTION: The slotted hole 10b of a lever 10 having the claw part 10a is engaged with the projection 2a of the cartridge holder 2, and the lever 10 is pressed on the side plane of the holder by a spring 11. When the cartridge 1 is inserted to a prescribed position, the above stated claw part 10a is engaged with the recessed part 12 on the side plane of the cartridge. And when the cartridge 1 is ejected, the claw part 10a is slided in a state being engaged with the recessed part 12, after it is slided by a distance of the slotted hole 10b, a projection 2a is abutted with the end face of the slotted hole, thereby, the sliding of the cartridge 1 is stopped. Thereby, the jumping quantity of the cartridge 1 outside a panel is kept at a constant level by the distance of the slotted hole, and the drop of the cartridge due to jumping can surely be prevented from being generated.