Opening/closing apparatus and molding apparatus

An opening/closing apparatus comprising:

• a fixed platen to which one of a pair of molds is to be mounted;
• a movable platen to which the other mold is to be mounted;
• a pressure-receiving platen connected to the fixed platen via tie bars;
• an opening/closing mechanism that opens and closes the molds by moving the movable platen back and forth, including a toggle link mechanism connecting the pressure-receiving platen and the movable platen, the toggle link mechanism including a link housing;
• a drive mechanism that drives the opening/closing mechanism;
• and
• at least one core-back hydraulic cylinder that applies a load to the movable platen in a given direction in conjunction with the drive mechanism, wherein the at least one core-back hydraulic cylinder is located between the link housing and the movable platen, connecting the movable platen with the pressure-receiving platen, and the load applied by the at least one core-back hydraulic cylinder to the movable platen is in such a direction as to eliminate a gap between a pin and a bush in a link connecting portion of the toggle link mechanism.