Container production method

A container production method of producing a container that contains a content liquid by liquid blow molding a synthetic resin preform, the method comprising:

• a preform setup step of disposing the preform in a blow molding mold that is releasable by being separated into a plurality of separated mold pieces and engaging a filling nozzle connected to a liquid supply path with a mouth of the preform;
• a blow molding step of liquid blow molding the preform into a shape conforming to a cavity of the blow molding mold by supplying a pressurized liquid supplied to the liquid supply path from the filling nozzle into the preform;
• a liquid discharge step of releasing the blow molding mold and pressing a trunk of a container after molding with a pressing portion that is inserted from a clearance between the separated mold pieces adjacent to each other to discharge a liquid in the container to outside of the container by a predetermined amount;
• and
• a headspace forming step of forming a headspace in the container by separating the filling nozzle from a mouth of the container after a predetermined amount of liquid is discharged to outside,
• wherein, in the liquid discharge step, with an inside of the container blocked with respect to the liquid supply path by closing the filling nozzle with a seal body and with a discharge path branched from the filling nozzle opened, the liquid in the container is discharged to outside through the discharge path by pressing the trunk of the container by the pressing portion,
• wherein in the headspace forming step, the filling nozzle is separated from the mouth after the discharge path is closed,
• wherein the filling nozzle is configured to be opened and closed with respect to the liquid supply path by the seal body, wherein the discharge path branched from the filling nozzle is provided in a portion of the filling nozzle opposite to the liquid supply path with respect to the portion closed by the seal body.