A sealed battery includes a battery case with a liquid inlet, a power generating element in the case, a lid member closing the liquid inlet and having a peripheral edge welded to the case over the entire circumference, a circular groove in the outer surface of the case and around the entire periphery of the liquid inlet, a peripheral portion provided over the entire periphery of a portion in the back surface of the lid member facing the liquid inlet, and a protrusion partially placed around the liquid inlet between the circular groove and the peripheral portion to form a clearance between the circular groove and the peripheral portion. The space facing the inner surface in a portion melted during welding between the peripheral edge and the case is continuous to the liquid inlet through a clearance formed by the protrusion between the circular groove and the peripheral portion.