It is to provide a packaging container comprising: a synthetic resin container body having a flange part at a periphery of an opening at an upper end thereof; and a container cap having a top board part and a skirt part provided such that it is suspended from a-periphery of the top board part, and wherein the top board part is heat-sealed onto an upper surface of the flange part of the container body; wherein the packaging container has a first cutout part at an upper end of an outer edge of the flange part. By providing a first cutout part, a packaging container possible to achieve sealing with the container cap stably, and to open the sealing easily and surely as well can be provided, by suppressing the effect of a molten resin on a folded corner part of the skirt of the container cap when the container body is heat-sealed with the container cap.