To provide a packaging container with anti-bulging function comprising a bag inside a box in which an inner bag is set in an octangular inner cylinder integrated with a quadrangular outer casing. The bag inside the box provides an anti-bulging function to prevent the outer casing from bulging, by developing a counter bulge in the inner bag acting on an oblique surface of the octangular inner cylinder to pull a side wall of the quadrangular outer casing inward.