A method of measuring current of a battery pack including a rechargeable battery, a main switch connected in series to the battery, and a pre-charge switch connected in parallel to the main switch, the method comprising: turning on the main switch and turning off the pre-charge switch; determining whether the current measured using a current sensor connected in series with said main switch is equal to or lower than a first critical value for a pre-set time period, wherein the first critical value corresponds to a standby current of the battery pack; and if the current measured is equal to or lower than the first critical value: turning on the pre-charge switch and turning off the main switch; measuring a voltage between both terminals of the main switch; calculating a pre-charge current flowing through the pre-charge switch by taking into consideration the resistance of a pre-charge resistor connected in series to the pre-charge switch; measuring current of the battery pack using the current sensor; comparing the current measured using the current sensor with the pre-charge current; and correcting an offset of the current sensor based on results of the comparison, wherein the correcting of the offset of the current sensor is performed when a difference between the pre-charge current and the current measured using the current sensor is equal to or greater than a second critical value. turning on the main switch and turning off the pre-charge switch; determining whether the current measured using a current sensor connected in series with said main switch is equal to or lower than a first critical value for a pre-set time period, wherein the first critical value corresponds to a standby current of the battery pack; and if the current measured is equal to or lower than the first critical value: turning on the pre-charge switch and turning off the main switch; measuring a voltage between both terminals of the main switch; calculating a pre-charge current flowing through the pre-charge switch by taking into consideration the resistance of a pre-charge resistor connected in series to the pre-charge switch; measuring current of the battery pack using the current sensor; comparing the current measured using the current sensor with the pre-charge current; and correcting an offset of the current sensor based on results of the comparison, wherein the correcting of the offset of the current sensor is performed when a difference between the pre-charge current and the current measured using the current sensor is equal to or greater than a second critical value. turning on the pre-charge switch and turning off the main switch; measuring a voltage between both terminals of the main switch; calculating a pre-charge current flowing through the pre-charge switch by taking into consideration the resistance of a pre-charge resistor connected in series to the pre-charge switch; measuring current of the battery pack using the current sensor; comparing the current measured using the current sensor with the pre-charge current; and correcting an offset of the current sensor based on results of the comparison, wherein the correcting of the offset of the current sensor is performed when a difference between the pre-charge current and the current measured using the current sensor is equal to or greater than a second critical value.