An apparatus for balancing a plurality of battery cells (Cell 1 to Cell n), comprising: a monitoring unit configured to detect a voltage of each of the plurality of series-connected battery cells (Cell 1 to Cell n); a balancing unit including a first common resistor element (R 1) and a switching module, the first common resistor element (R 1) connected between a first common node (N 1) and a second common node (N 2); and a control unit operably coupled to the monitoring unit and the switching module, wherein the switching module is configured to: selectively connect a positive electrode terminal of each battery cell (Cell 1 to Cell n) to the first common node (N 1), and selectively connect a negative electrode terminal of each battery cell (Cell 1 to Cell n) to the second common node (N 2), and characterized in that the control unit is configured to: determine a maximum number of battery cells (Cell 1 to Cell n) that can be included in a balancing target based on the resistance of the first common resistor element (R 1), the voltage of each of the plurality of battery cells (Cell 1 to Cell n) and an upper limit of balancing current, determine the balancing target including at least one of the plurality of battery cells (Cell 1 to Cell n) based on the voltage of each of the plurality of battery cells, wherein the number of at least one of the plurality of battery cells (Cell 1 to Cell n) determined as the balancing target is equal to or smaller than the maximum number of battery cells (Cell 1 to Cell n), and control the switching module to form a current channel between the first common resistor element (R 1) and the balancing target. a monitoring unit configured to detect a voltage of each of the plurality of series-connected battery cells (Cell 1 to Cell n); a balancing unit including a first common resistor element (R 1) and a switching module, the first common resistor element (R 1) connected between a first common node (N 1) and a second common node (N 2); and a control unit operably coupled to the monitoring unit and the switching module, wherein the switching module is configured to: selectively connect a positive electrode terminal of each battery cell (Cell 1 to Cell n) to the first common node (N 1), and selectively connect a negative electrode terminal of each battery cell (Cell 1 to Cell n) to the second common node (N 2), and characterized in that the control unit is configured to: determine a maximum number of battery cells (Cell 1 to Cell n) that can be included in a balancing target based on the resistance of the first common resistor element (R 1), the voltage of each of the plurality of battery cells (Cell 1 to Cell n) and an upper limit of balancing current, determine the balancing target including at least one of the plurality of battery cells (Cell 1 to Cell n) based on the voltage of each of the plurality of battery cells, wherein the number of at least one of the plurality of battery cells (Cell 1 to Cell n) determined as the balancing target is equal to or smaller than the maximum number of battery cells (Cell 1 to Cell n), and control the switching module to form a current channel between the first common resistor element (R 1) and the balancing target. selectively connect a positive electrode terminal of each battery cell (Cell 1 to Cell n) to the first common node (N 1), and selectively connect a negative electrode terminal of each battery cell (Cell 1 to Cell n) to the second common node (N 2), and characterized in that the control unit is configured to: determine a maximum number of battery cells (Cell 1 to Cell n) that can be included in a balancing target based on the resistance of the first common resistor element (R 1), the voltage of each of the plurality of battery cells (Cell 1 to Cell n) and an upper limit of balancing current, determine the balancing target including at least one of the plurality of battery cells (Cell 1 to Cell n) based on the voltage of each of the plurality of battery cells, wherein the number of at least one of the plurality of battery cells (Cell 1 to Cell n) determined as the balancing target is equal to or smaller than the maximum number of battery cells (Cell 1 to Cell n), and control the switching module to form a current channel between the first common resistor element (R 1) and the balancing target. determine a maximum number of battery cells (Cell 1 to Cell n) that can be included in a balancing target based on the resistance of the first common resistor element (R 1), the voltage of each of the plurality of battery cells (Cell 1 to Cell n) and an upper limit of balancing current, determine the balancing target including at least one of the plurality of battery cells (Cell 1 to Cell n) based on the voltage of each of the plurality of battery cells, wherein the number of at least one of the plurality of battery cells (Cell 1 to Cell n) determined as the balancing target is equal to or smaller than the maximum number of battery cells (Cell 1 to Cell n), and control the switching module to form a current channel between the first common resistor element (R 1) and the balancing target.