Abstract: A liquid-filled container manufacturing method including: the air discharge step of discharging air from an inside of a preform, by supplying a liquid at a level of pressure that does not cause stretching of the preform to the inside of the preform through an intra-tube channel formed between an inner peripheral surface of a spare supply tube extending through a blow nozzle and an outer peripheral surface of a spare supply rod provided radially inward thereof; and the liquid blow molding step of molding the preform into a container with a shape conforming to an inner surface of a mold, by stretching the preform downward using the spare supply rod and supplying a pressurized liquid to the inside of the preform through an intra-nozzle channel formed between an inner peripheral surface of the blow nozzle and the outer peripheral surface of the spare supply rod.