Paper container

A paper container, which is a gable roof type and is formed of a paperboard material having a thermoplastic resin laminated on each of a front surface and a back surface of the paperboard material, the paper container comprising:

• four body panels;
• a vertical direction sealing panel, which joins edge portions of the four body panels so that the four body panels form a quadrangular body;
• a pair of gable roof forming panels, which are contiguous with upper ends of the body panels, and include outer-side top sealing panels at upper portions of the pair of gable roof forming panels, respectively, and are opposed to each other;
• a pair of gable wall forming panels, which are contiguous with upper ends of the body panels through top portion horizontal folding lines, and include inner-side top sealing panels at upper portions of the pair of gable wall forming panels, respectively, and are opposed to each other, any one of the pair of gable wall forming panels being formed into a pouring spout to be unsealed;
• and
• a top portion formed by folding the pair of gable wall forming panels between the pair of gable roof forming panels, and by heating, sealing, and tightly closing the outer-side top sealing panels and the inner-side top sealing panels at predetermined positions,
• wherein on an unsealed-side body panel among the four body panels, which is contiguous with the unsealed-side gable wall forming panel through a top portion horizontal folding line, a first auxiliary folding line having a downwardly curved shape is formed to have:
• a left end portion arranged at or near an intersection of an end portion of a body vertical folding line on the left of the unsealed-side body panel and a left end portion of the top portion horizontal folding line;
• a right end portion arranged at or near an intersection of an end portion of a body vertical folding line on the right of the unsealed-side body panel and a right end portion of the top portion horizontal folding line;
• and a lowest point located at a center of the body panel in a right-and-left direction of the body panel, and below the first auxiliary folding line and at a predetermined distance from the first auxiliary folding line, a second auxiliary folding line having a downwardly curved shape is formed to have:
• a left end portion arranged at or near the intersection of the end portion of the body vertical folding line on the left of the body panel and the left end portion of the top portion horizontal folding line;
• a right end portion arranged at or near the intersection of the end portion of the body vertical folding line on the right of the body panel and the right end portion of the top portion horizontal folding line;
• and a lowest point located at the center of the body panel in the right-and-left direction.