A secondary cell manufacturing method includes the steps of: disposing a cap including a magnetic body so as to cover a liquid injection hole provided in a lid member; disposing the lid member so as to cover an opening of an outer case; and bringing close to each other the magnetic body and a magnetic body that applies a magnetic force to the magnetic body, and so holding the position of the cap that is disposed to cover the liquid injection hole by the magnetic force applied from the magnetic body to the magnetic body.