Paper container

A paper container, which includes a gable roof and is formed of a paperboard material having a thermoplastic resin laminated on each of a front surface of the paperboard material 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 tubular body;
• two gable roof forming panels, which are contiguous with upper ends of a first pair of the four body panels, and include outer-side top sealing panels at upper portions of the two gable roof forming panels, respectively, and are opposed to each other;
• two gable wall forming panels, which are contiguous with upper ends of a second pair of the four body panels, and include inner-side top sealing panels at upper portions of the two gable wall forming panels, respectively, and are opposed to each other, any one of the two gable wall forming panels being configured to be formed into a pouring spout to be unsealed;
• and
• a top portion formed by folding the two gable wall forming panels between the two gable roof forming panels, and by heating, sealing, and closing the outer-side top sealing panels and the inner-side top sealing panels at predetermined positions,
• wherein, in an unsealed-side body panel among the four body panels, which is contiguous with an unsealed-side gable wall forming panel among the two gable wall forming panels through a top portion horizontal folding line, reference points are respectively set on body vertical folding lines that are located on both sides of the unsealed-side body panel,
• wherein each of the reference points is distant by 3 mm or more from an intersection of an end portion of one of the body vertical folding lines and an end portion of the top portion horizontal folding line,
• wherein, on the unsealed-side body panel, a first auxiliary folding line having an upwardly curved shape is formed to have end portions arranged so as to connect the reference points to each other, or connect together positions that are near the reference points on the body vertical folding lines or positions that are away from the body vertical folding lines and below the reference points in a height direction of each of the body vertical folding lines,
• wherein the end portions of the first auxiliary folding line, which connect together the positions that are near the reference points on the body vertical folding lines or the positions that are away from the body vertical folding lines and below the reference points in the height direction, are each distant from the intersection by 3 mm or more and by a range within a length equal to or smaller than 20% of a length of the top portion horizontal folding line, and
• wherein a second auxiliary folding line extends along a vertical centerline of the paper container and is formed on at least one of the unsealed-side body panel or a substantially triangular surface portion of the unsealed-side gable wall forming panel.