A container molding apparatus that is adapted for molding a preform formed of a thermoplastic resin into a container having a predetermined shape, the container molding apparatus comprising: a mold having a cavity in which the preform heated to a predetermined temperature is to be disposed; a filling nozzle that is connected to a content liquid containing tank containing a content liquid and that is configured to engage with a mouth of the preform disposed in the cavity; a sealing member that is provided in a flow path between the content liquid containing tank and the filling nozzle and that is configured to open and close the flow path; and a vacuum pump that is connected to the cavity and that is configured to depressurize an inside of the cavity to a negative pressure, wherein the apparatus is configured such that by placing the inside of the cavity in which the preform is disposed under the negative pressure by the vacuum pump in a state where the sealing member is opened, the preform is stretched into the predetermined shape conforming to an inner surface of the cavity by the negative pressure, and the content liquid is introduced from the content liquid containing tank into the preform through the filling nozzle by a negative pressure generated inside the preform at the time of stretching, the apparatus being characterised in further comprising a stretching rod configured to stretch the preform in an axial direction, and wherein the apparatus is configured such that by withdrawing the stretching rod from the container after molding of the container, the level of the liquid surface of the content liquid contained within the container, that is, the amount of the content liquid contained in the container, is set appropriately. a mold having a cavity in which the preform heated to a predetermined temperature is to be disposed; a filling nozzle that is connected to a content liquid containing tank containing a content liquid and that is configured to engage with a mouth of the preform disposed in the cavity; a sealing member that is provided in a flow path between the content liquid containing tank and the filling nozzle and that is configured to open and close the flow path; and a vacuum pump that is connected to the cavity and that is configured to depressurize an inside of the cavity to a negative pressure, wherein the apparatus is configured such that by placing the inside of the cavity in which the preform is disposed under the negative pressure by the vacuum pump in a state where the sealing member is opened, the preform is stretched into the predetermined shape conforming to an inner surface of the cavity by the negative pressure, and the content liquid is introduced from the content liquid containing tank into the preform through the filling nozzle by a negative pressure generated inside the preform at the time of stretching, the apparatus being characterised in further comprising a stretching rod configured to stretch the preform in an axial direction, and wherein the apparatus is configured such that by withdrawing the stretching rod from the container after molding of the container, the level of the liquid surface of the content liquid contained within the container, that is, the amount of the content liquid contained in the container, is set appropriately.