A container manufacturing method includes: a liquid discharge step in which a predetermined amount of liquid (L) in the container (C) is discharged to the outside by supplying pressurized air from air holes (13) provided in a blow molding mold (11) to a cavity (12) and pushing an outer surface of the container (C) after molding by the air; and a headspace forming step in which a headspace (HS) is formed in the container (C) by separating a filling nozzle (22) from a mouth portion (Ca) of the container (C) in a state in which a predetermined amount of liquid (L) is discharged to the outside.