A cylindrical battery with an opening sealing body that seals an opening of a battery can. The opening sealing body includes a valve member, a metal plate disposed on an inner side of the battery with respect to the valve member, and an annular insulating member interposed between the valve member and the metal plate. The valve member and the metal plate are connected to each other at respective central portions. The valve member has an annular thin-walled portion which is deformable when an internal pressure of the battery increases. The metal plate and the insulating member have respective holes which communicate with each other. The insulating member has a section that covers a surface, on the valve member side, of the metal plate, and a section that is provided subsequent to the section and covers a lateral surface of the hole of the metal plate.