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.