PURPOSE: To eliminate generation of a jam when paper sheets are stored, by providing pressure sensors, which detect the first pressure value and the second pressure value larger than the first pressure value, in the upper of a lift and measuring a height difference between the both sensors due to pressing force of the accumulated paper sheets on the lift so that an optimum lowering position of the lift is determined.

CONSTITUTION: The first and second pressure detecting levers 16, 14 are swivelably provided coaxially with a paper sheet releasing roller 7, and the levers form protrusion parts in their point end parts, actuating photo sensors 11, 12 when the levers are turned to the upper. A device urges downward the lever 16 by its dead weight while the lever 14 by a spring 15. Paper sheets on a lift 1a are lifted successively turning on the sensors 12, 11, and a number of pulses during this time are counted. This counted value refers a preset restoration amount to a table, and the lift is lowered so that an ideal head is obtained from the roller 7 to an upper surface of the paper sheets. In this way, generation of a jam can be prevented when the paper sheet is accumulated.