PURPOSE: To remove the flashes of a molded piece and to prolong the service life of a mold by operating the sliding pieces on the external circumference of the molded piece toward the outside and then projecting the molded piece with a projecting sleeve fixed to a projecting plate.

CONSTITUTION: The projecting sleeve 3 is fixed by a tightening bolt 4 to the floating plate 14 on the movable side. When a space is made between the retainer plate 13 on the fixed side and the floating plate 14 on the movable side by the opening of the mold, the slide piece 5 in the segmental structure is moved by the angular pin 6 toward the outside. When the knockout bar 12 on the press side pushes the knockout plate 11, the floating plate 14 on the movable side connecting to the return pin 8 is knocked out. The knockout sleeve 3 knocks out the molded piece 1 by this movement. Said structure removes flashes generated due to the wear from a partitioning section, breaks on the knockout sleeve 3 decrease and the service life of the mold improves.