To provide a packaging container consisting of a combination of a plastic bottle and a cap, which can be prevented from being damaged on an internal surface or a top face of a bottle mouth by changing the shape of the mouth of the plastic bottle, and preventing an inner ring side face of the cap from getting damaged when fitted, and can prevent leakage of contents.

The packaging container Z consisting of a combination of the plastic bottle X and the cap Y is equipped with a corner R1 at the uppermost end of the internal surface 1 of the mouth 9 of the bottle X and a first straight portion 3 extending horizontally from the top face of the corner R1 to the bottom of the bottle X. A step L is provided toward an inner diameter ΦA of the mouth 9 in the straight portion 3, and in addition, a corner R2 is provided at the lower end of the straight portion 3.