PURPOSE: To allow the continuous separation of soft works by instructing a set distance to a switching suction area corresponding to a selected damper device to a distance counter circuit, when a work reaches the switching suction area.

CONSTITUTION: When a work 5 reaches a switching suction area, a distance counter circuit 34 instructs the operation of a damper device 12c to an opening and closing control circuit 31, whereby the work 5 is separated from a vacuum conveyor 7 and fallen down in the switching suction area. The works 5 are fallen continuously in this switching suction area, and when a determined number of pieces is counted up by a piece number counter circuit 32, the switching of the damper device 12c which is an operating target is instructed to the opening and closing control circuit 31 by a damper selecting circuit 33, and a set distance to a switching suction area corresponding to the newly selected damper device 12c is instructed to a distance counter circuit 34 by a damper position setting circuit 35. Thus, soft works 5 can be separated every determined number of pieces.