PURPOSE: To automatically carry out reset by installing an sensor for detecting the presence of paper on a receiving board onto a stacker receiving board and reset-operating a receiving board raising/lowering driving means by the output of the sensor.

CONSTITUTION: A stacker receiving board 53 is raised and lowered by an elevation driving means 3. Continuous paper sheets 51 are assorted and piled in foldable manners by the assorting rollers 55 and 56 onto a stacker receiving board 53, and the receiving board 53 is lowered by the weight. When the continuous paper 51 is taken out from the receiving board 53 after the completion of work, it is detected that the paper 51 is taken out, by a sensor installed onto the receiving board 53, and the elevation driving means 3 is automatically reset-operated, and the stacker receiving board 53 is reset. Since reset is carried out automatically, the trouble due to the forgetting to reset is dissolved.