A plurality of rotatable small table are disposed on a rotatable large table, and a workpiece is mounted on the small tables. Above a projection range in the large table, a pressing part is provided. The pressing part is elevated and lowered by an elevating/lowering mechanism between a withdrawn position spaced above the workpiece on the small table and a pressing position for pressing the workpiece on the small table from above. Also, the pressing part is rotationally driven coaxially with a rotary shaft of the small table and in the same rotating direction and at the same rotating speed as the small table, by a third drive mechanism.