An apparatus for balancing charge capacity of a battery cell, comprising: a voltage sensing and discharging circuit including a battery having a cell group, a switching unit for selectively connecting both terminals of each battery cell of the cell group to first and second conductive lines (1,2), a capacitor C connected to the first and second conductive lines (1,2) in parallel, a voltage amplifying unit connected to both terminals of the capacitor C via a first switch, and a discharge resistance connected to both terminals of the capacitor C in series via a second switch; and a voltage balancing unit for: (i) subsequently controlling the switching unit in an OFF state of the first and second switches (SW1, SW2) to connect both terminals of each battery cell of the cell group to the first and second conductive lines (1,2) to charge the capacitor C with a voltage of each battery cell, (ii) controlling the first switch to turn on to sense a charged voltage of the charged capacitor C so that the voltage of each battery cell is sensed after disconnecting each battery cell from the first and second conductive lines, (iii) then selectively controlling the switching unit, in an OFF state of the first and second switches, to connect both terminals of a battery cell that requires charge capacity balancing to the first and second conductive lines (1,2) to charge the capacitor C with a voltage of the battery cell that needs balancing of charge capacity, and (iv) controlling the second switch to turn on to discharge the charged voltage of the capacitor C through the discharge resistance after disconnecting the battery cell that requires charge capacity balancing from the first and second conductive line so that the charge capacity of the battery is balanced. a voltage sensing and discharging circuit including a battery having a cell group, a switching unit for selectively connecting both terminals of each battery cell of the cell group to first and second conductive lines (1,2), a capacitor C connected to the first and second conductive lines (1,2) in parallel, a voltage amplifying unit connected to both terminals of the capacitor C via a first switch, and a discharge resistance connected to both terminals of the capacitor C in series via a second switch; and a voltage balancing unit for: (i) subsequently controlling the switching unit in an OFF state of the first and second switches (SW1, SW2) to connect both terminals of each battery cell of the cell group to the first and second conductive lines (1,2) to charge the capacitor C with a voltage of each battery cell, (ii) controlling the first switch to turn on to sense a charged voltage of the charged capacitor C so that the voltage of each battery cell is sensed after disconnecting each battery cell from the first and second conductive lines, (iii) then selectively controlling the switching unit, in an OFF state of the first and second switches, to connect both terminals of a battery cell that requires charge capacity balancing to the first and second conductive lines (1,2) to charge the capacitor C with a voltage of the battery cell that needs balancing of charge capacity, and (iv) controlling the second switch to turn on to discharge the charged voltage of the capacitor C through the discharge resistance after disconnecting the battery cell that requires charge capacity balancing from the first and second conductive line so that the charge capacity of the battery is balanced. (i) subsequently controlling the switching unit in an OFF state of the first and second switches (SW1, SW2) to connect both terminals of each battery cell of the cell group to the first and second conductive lines (1,2) to charge the capacitor C with a voltage of each battery cell, (ii) controlling the first switch to turn on to sense a charged voltage of the charged capacitor C so that the voltage of each battery cell is sensed after disconnecting each battery cell from the first and second conductive lines, (iii) then selectively controlling the switching unit, in an OFF state of the first and second switches, to connect both terminals of a battery cell that requires charge capacity balancing to the first and second conductive lines (1,2) to charge the capacitor C with a voltage of the battery cell that needs balancing of charge capacity, and (iv) controlling the second switch to turn on to discharge the charged voltage of the capacitor C through the discharge resistance after disconnecting the battery cell that requires charge capacity balancing from the first and second conductive line so that the charge capacity of the battery is balanced.