To provide suitable tension to a surface of a packaging film which is filled with raw materials, to which a first lateral seal is applied and which is formed into a bag shape.

A longitudinal sealing device is formed into a roughly cylindrical shape by sealing together ends along the flowing direction of a conveyed packaging film. A first lateral sealing device seals the roughly cylindrical packaging film in a width direction to form a first lateral sealed portion, thereby forming a bag shape. A filling device fills the inside of the packaging film with a content when the packaging film is formed into the bag shape by the first lateral sealing device. A second lateral sealing device applies sealing to a region including the content-housed part of the bag-shaped packaging film filled with the content to form a second lateral sealing part. By the second lateral sealing part, the percentage of the content in the content-housed part increases.