A power storage device having a plurality of modules having a secondary battery, a charging switch for controlling the charging of the secondary battery, a discharging switch for controlling the discharging of the secondary battery, and a voltage measurement unit for measuring the module voltage and a switch control unit for controlling the charging switches, the discharging switches, or both, wherein the plurality of modules are connected in parallel and the switch control unit keeps the discharge switch of at least one module on for a prescribed period of time and controls the charging switches of modules that have a maximum module charging current, which is estimated on the basis of the module voltage, that is less than or equal to a prescribed value so as to be in an on state.