Provided is a technique for suppressing welding faults caused in sealing a case of a sealed battery by laser welding. A step for manufacturing a sealed battery having a case sealed by a sealing plug and a sealing plate, which includes a sealing step for fitting the sealing plug into a pouring hole formed in a recess of a lid portion and inserting the sealing plate into the recess, and a welding step for joining the sealing plate to the recess by laser welding. In the sealing step, a heat-insulating member is provided in a minute space defined by the recess, the sealing plug and the sealing plate so as to block at least a part of the boundary portion between the sealing plate and the recess. In the welding step, welding is completed at a position where the heat-insulating member is present in the boundary portion.