The present invention provides a port that more reliably prevents a sealing plug from falling out of the port body. This port is provided with a sealing plug which can be punctured by a hollow needle, a hollow port body inside which the sealing plug is disposed, and a retaining member attached to the port body. The port body has a cylindrical sealed part in which the sealing plug is enclosed, and an engaged part formed in the sealed part. The retaining member has a body part that is inside the sealed part and has a first surface facing a first end of the sealed part, a restricting part that is formed on the first surface of the body part, and restricts the movement of the sealed part in the sealing plug toward a second end, and an engaging part that engages with the engaged part of the port body.
