PURPOSE: To certainly perform the return of the ejector plate after the ejection of a product in an injection molding machine.

CONSTITUTION: A connection means is provided between the ejector rod 13 on the side of a molding machine and the movable mounting plate 2 of a mold and, when the ejector rod 13 ejects a product from the mold to return toward the molding machine, the movable mounting plate 12 also returns simultaneously by the connection means. Since the connection means is constituted of a magnetic means or a hook engaging means, the operation of the connection means becomes certain and stable.