In a work table apparatus for a plate material processing machine, a group of work supporting belts each extending in a work feed direction and divided in the direction perpendicular to the work feed direction are arranged so as to form a work table surface separated into front and rear support portions on both sides of a plate material processing section, and the work supporting belts are driven in the work feed direction in synchronism with the movement of the plate material to be processed. Therefore, no relative displacement is produced between the work support portions of the work supporting belts and the plate material to be processed. Thus, punched products of small size can be supported securely without damaging the microjoint portions of the processed products, scratching the plate material, and producing sound noise. Further, since the work support portions can be lowered selectively from the work pass line, downward projecting portions can be formed in the plate material and further the downward formed projecting portions can be supported by the lowered work support portions, thus preventing the downward deflection of the processed material. Further, since the front and rear side work support portions can be moved or urged horizontally toward each other, it is possible to effectively support the plate material by reducing as much as possible the area at which the plate material is not supported by the belts.