PURPOSE: To obviate the stop, etc., of the device by an erroneous detection and to improve reliability by making judgment that a container is full of paper leaves when the detection of the paper leaves by reflection type optical sensors continues for a specified period of time or longer by a full detecting means.
CONSTITUTION: The paper leaves charged to the device are shredded and the shredded paper leaves are deposited and stored in the container 11. The reflection type optical sensors 5, 6 are installed toward this container 1. The full detecting means judges that the container 11 is full of the paper leaves when the detection of the paper leaves by the reflection type optical sensors 5, 6 continues for the specified period of time or longer. As a result, the paper leaves under falling (shredding dust) and the deposited paper leaves (shredding dust) are surely identified and the stop, etc., of the device by the erroneous detection are obviated and the reliability is improved.