An apparatus and method for discharging a voltage in a battery pack. The apparatus includes a discharge resistance connected to a discharge target battery of plural batteries in the battery pack and discharging a voltage of the discharge target battery, a switching section for connecting the discharge target battery and the discharge resistance, a voltage measuring section for measuring a voltage of the discharge target battery, and a control section for controlling the switching section depending on the measured voltage value of the battery. The method includes measuring a voltage of the discharge target battery, calculating a PWM duty rate of a switching section connecting the discharge target battery and a discharge resistance using the measured voltage value and a value of the discharge resistance, and controlling the switching section based on the duty rate to maintain an energy consumed in the discharge resistance to be constant.