A film-forming device comprising: a chamber which has a film-forming chamber accommodating a container for forming a gas barrier film, wherein the film-forming device is configured such that the film-forming chamber is in a vacuum state when the gas barrier film is formed; a gas supply pipe which has a gas flow channel for introducing a medium gas for forming the gas barrier film into the container and is moveable upward and downward along an axis line direction thereof; a cylinder in which the gas supply pipe is arranged movably upward and downward; and a heat generating body configured to generate heat when power is supplied, wherein the gas supply pipe includes a first supply pipe adapted to advance and retreat in the film-forming chamber, wherein the first supply pipe internally has a first gas flow channel, and wherein the first supply pipe is adapted to discharge the medium gas from a tip end toward the heat generating body, and a second supply pipe which internally has a second gas flow channel in communication with the first gas flow channel and is connected to the first supply pipe, wherein the cylinder includes a first cylinder in which the first supply pipe is arranged movably upward and downward, has a pressure-reducing chamber in communication with the first gas flow channel, and is fixed to the chamber, and a second cylinder in which the second supply pipe is arranged movably upward and downward and has a storage chamber in communication with the second gas flow channel, and wherein the film forming device is configured such that medium gas supplied to the storage chamber passes through the second supply pipe and the first supply pipe in this order and is supplied to the container. a chamber which has a film-forming chamber accommodating a container for forming a gas barrier film, wherein the film-forming device is configured such that the film-forming chamber is in a vacuum state when the gas barrier film is formed; a gas supply pipe which has a gas flow channel for introducing a medium gas for forming the gas barrier film into the container and is moveable upward and downward along an axis line direction thereof; a cylinder in which the gas supply pipe is arranged movably upward and downward; and a heat generating body configured to generate heat when power is supplied, wherein the gas supply pipe includes a first supply pipe adapted to advance and retreat in the film-forming chamber, wherein the first supply pipe internally has a first gas flow channel, and wherein the first supply pipe is adapted to discharge the medium gas from a tip end toward the heat generating body, and a second supply pipe which internally has a second gas flow channel in communication with the first gas flow channel and is connected to the first supply pipe, a first supply pipe adapted to advance and retreat in the film-forming chamber, wherein the first supply pipe internally has a first gas flow channel, and wherein the first supply pipe is adapted to discharge the medium gas from a tip end toward the heat generating body, and a second supply pipe which internally has a second gas flow channel in communication with the first gas flow channel and is connected to the first supply pipe, wherein the cylinder includes a first cylinder in which the first supply pipe is arranged movably upward and downward, has a pressure-reducing chamber in communication with the first gas flow channel, and is fixed to the chamber, and a second cylinder in which the second supply pipe is arranged movably upward and downward and has a storage chamber in communication with the second gas flow channel, and a first cylinder in which the first supply pipe is arranged movably upward and downward, has a pressure-reducing chamber in communication with the first gas flow channel, and is fixed to the chamber, and a second cylinder in which the second supply pipe is arranged movably upward and downward and has a storage chamber in communication with the second gas flow channel, and wherein the film forming device is configured such that medium gas supplied to the storage chamber passes through the second supply pipe and the first supply pipe in this order and is supplied to the container.