A sufficient sealing property of a through hole is ensured. A sealing structure includes a cylindrically-shaped body part inserted into the through hole, formed of a thin plate of a first thickness, one end of the body part being open and another end of the body part being closed, a tapered part connected to the opened one end of the body part and including a diameter gradually expanding outward as a distance from the body part increases, and a first bent part connected to the tapered part, formed of a thin plate thinner than the first thickness, and bent inward so that a protruding part protruding outward elastically abuts against an inner peripheral surface of the through hole.