An auto management system for an air filter used in a battery pack comprises at least one cell and a case accommodating each of the cells so that there is secured an air flow passage between the neighboring cells. The battery pack is provided with an air inlet at one side and an air outlet on the other side and comprises an air filter detachably mounted at an outside end of the air inlet of the case; a blowing fan provided to one of the air inlet and the air outlet; a flux sensor; a control unit connected to the cells of the battery pack, the blowing fan and the flux sensor, respectively, measuring currents, voltages and temperatures of the respective cells and electrically controlling the blowing fan and the flux sensor.