Liquid-containing container manufacturing method

A liquid-containing container manufacturing method of manufacturing a liquid-containing container containing a content liquid from a synthetic resin-made preform using a mold for blow molding and a nozzle unit that includes:

• a nozzle unit body having an annular seat part provided in a supply path of a liquid;
• a seal body movable between a closed position at which the seat part is closed and an open position at which the seat part is open;
• and an opening-closing body capable of opening and closing a preliminary supply path that is formed inside the seal body and communicates with a part of the supply path upstream from the seat part, the liquid-containing container manufacturing method comprising:
• an air discharge step of discharging air inside the preform placed in the mold for blow molding to outside, by opening the preliminary supply path by the opening-closing body in a state in which the seal body is at the closed position to supply the liquid from the preliminary supply path into the preform;
• and
• a liquid blow molding step of molding the preform into the liquid-containing container of a shape along an inner surface of the mold for blow molding, by moving the seal body from the closed position to the open position to supply the liquid pressurized into the preform through the seat part.