A vacuum suction system comprises a work conveyor table 2 having work receiving openings 5, and a table base 3 having vacuum suction channels 7 which communicate with the work receiving openings 5 of the conveyor table 2. The work receiving openings 5 and the vacuum suction channels 7 communicate with a vacuum generation source 17 via a vacuum pipe 9. A negative pressure sensor 10 is disposed on the vacuum pipe 9. Based on a signal from the negative pressure sensor 10, a compressed air generation source 20 supplies a compressed air to the vacuum pipe 9 and thereby stabilizes the vacuum level in the vacuum pipe 9.