A power storage system, comprising: a plurality of power storage modules (31, 50) that are connected in parallel to a power line; and a system voltage acquisition unit configured to obtain a system voltage (Vsys10) in the power line, wherein each of the power storage modules (31, 50) includes - a power storage section that is formed of one or more storage batteries, - a battery management unit configured to monitor a state of the power storage section and to control charging/discharging operations of the power storage section, the state comprising a battery voltage (Vbatt10) of the power storage section, and - a current control unit configured to control, according to the system voltage (Vsys10) and the battery voltage (Vbatt10), the current that flows between the power storage section and the power line, wherein the current control unit includes at least one variable resistor, and a resistance control unit (41, 51) configured to set a resistance value of the variable resistor, wherein the resistance control unit (41, 51) is configured to obtain the system voltage (Vsys10) from the system voltage acquisition unit and the battery voltage (Vbatt10) from the battery management unit, and wherein the resistance control unit (41, 51) is configured to set the resistance value such that the current that flows between the power storage section and the power line is equal to or smaller than a predetermined current value, if a value obtained based on the system voltage (Vsys10) and the battery voltage (Vbatt10) is larger than a predetermined value. a plurality of power storage modules (31, 50) that are connected in parallel to a power line; and a system voltage acquisition unit configured to obtain a system voltage (Vsys10) in the power line, wherein each of the power storage modules (31, 50) includes - a power storage section that is formed of one or more storage batteries, - a battery management unit configured to monitor a state of the power storage section and to control charging/discharging operations of the power storage section, the state comprising a battery voltage (Vbatt10) of the power storage section, and - a current control unit configured to control, according to the system voltage (Vsys10) and the battery voltage (Vbatt10), the current that flows between the power storage section and the power line, - a power storage section that is formed of one or more storage batteries, - a battery management unit configured to monitor a state of the power storage section and to control charging/discharging operations of the power storage section, the state comprising a battery voltage (Vbatt10) of the power storage section, and - a current control unit configured to control, according to the system voltage (Vsys10) and the battery voltage (Vbatt10), the current that flows between the power storage section and the power line, wherein the current control unit includes at least one variable resistor, and a resistance control unit (41, 51) configured to set a resistance value of the variable resistor, at least one variable resistor, and a resistance control unit (41, 51) configured to set a resistance value of the variable resistor, wherein the resistance control unit (41, 51) is configured to obtain the system voltage (Vsys10) from the system voltage acquisition unit and the battery voltage (Vbatt10) from the battery management unit, and wherein the resistance control unit (41, 51) is configured to set the resistance value such that the current that flows between the power storage section and the power line is equal to or smaller than a predetermined current value, if a value obtained based on the system voltage (Vsys10) and the battery voltage (Vbatt10) is larger than a predetermined value.