PURPOSE: To provide a mechanism interrupting the insertion of cartridges other than a normal cartridge.

CONSTITUTION: A restraining member 14 is mounted on the bottom surface 11a of a part 11 for loading the cartridge 13 and kept to rotate clockwise by a pressing force of an elastic member 16. When a specified cartridge 13 is inserted, a front end part of the cartridge 13 is made to abut on a spiral cam of the restraining member 14, and the restraining member 14 is turned counterclockwise. At this time, a restraining part 14c is fallen down and a fitting member 17 is engaged with a notch 14d. Then, the cartridge 13 is transported to the sitting position by a holder 18. When an unspecified cartridge is inserted, the restraining part 14c is not fallen down since the restraining member 14 is not sufficiently rotated, then the cartridge 13 is not be inserted furthermore.