shutter support unit 42 attached to the sixth gear 86 is also rotated in the anticlockwise direction in fig9 about the shaft 86 a as a result the shutter 40 is moved from the opening position as shown in fig2 to the closing position as shown in fig1 as described above the torque limiter 84 is provide between the shutter support unit 42 for supporting the shutter 40 and the shutter drive unit 50 therefore in the case the operator moves the shutter 40 downward by hand from the closing position shown in fig1 when the force applied from the operator to the torque limiter 84 is greater than the preset torque the torque limiter 84 releases the connection between the fourth gear 83 and the fifth gear 85 as such the fifth gear 85 can be rotated freely relative to the fourth gear 83 namely in this case the torque limiter 84 serves to block the driving force of the shutter drive unit 50 to be transmitted to the shutter 40 therefore even in the period during which the counting process for the paper sheets p is performed by the recognition and counting unit 24 the operator can move the shutter 40 downward by hand from the closing position shown in fig1 thereby to take out the paper sheets p from the stacking unit 26 further even in the case the hand or the like of the operator is placed in the stacking unit 26 in a period during which the shutter.