In a power storage system, a management device calculates a state of power (SOP) of a whole of a plurality of power storage blocks connected in parallel based on an SOP of each of the plurality of power storage blocks to specify the calculated SOP of the whole for an upper limit level of power or current for at least one of charging and discharging controlled by a power converter. When at least one of a plurality of switches is turned off to disconnect at least one (30) of the plurality of power storage blocks, the management device calculates an SOP of a whole of the remaining power storage blocks based on a deviation in current between each of the remaining power storage blocks to determine an upper limit level of power or current flowing into the power converter.