A battery pack, comprising: a first battery contactor and a second battery contactor respectively having one end electrically connected to a positive electrode terminal and a negative electrode terminal of a battery; a first charging contactor and a second charging contactor respectively having one end electrically connected to the other end of the first battery contactor and the other end of the second battery contactor; a first measurement resistor, a second measurement resistor and a third measurement resistor, wherein the first measurement resistor is electrically connected between a first node located at one end of the second charging contactor and a second node located at one end of the first charging contactor, and wherein the second measurement resistor is electrically connected between the first node and a third node located at the other end of the first charging contactor, and wherein the third measurement resistor is electrically connected between the first node and a fourth node located at the other end of the second charging contactor, respectively; a first power connector having a first input terminal and a second input terminal electrically connected to the other end of the first charging contactor and the other end of the second charging contactor, respectively; and a control unit configured to, when a second power connector of a charger having a first output terminal and a second output terminal respectively, electrically connected to the first input terminal and the second input terminal, is connected to the first power connector and a charging end request signal is received, control the first charging contactor and the second charging contactor into a turn-off state, when the charging end request signal is received since the charging is completed or stopped in a state where the first power connector of the battery pack is connected to the second power connector of the charger, and diagnose a fault of each of the first charging contactor and the second charging contactor based on at least one of a first measured voltage, a second measured voltage and a third measured voltage respectively applied to the first measurement resistor, the second measurement resistor and the third measurement resistor. a first battery contactor and a second battery contactor respectively having one end electrically connected to a positive electrode terminal and a negative electrode terminal of a battery; a first charging contactor and a second charging contactor respectively having one end electrically connected to the other end of the first battery contactor and the other end of the second battery contactor; a first measurement resistor, a second measurement resistor and a third measurement resistor, wherein the first measurement resistor is electrically connected between a first node located at one end of the second charging contactor and a second node located at one end of the first charging contactor, and wherein the second measurement resistor is electrically connected between the first node and a third node located at the other end of the first charging contactor, and wherein the third measurement resistor is electrically connected between the first node and a fourth node located at the other end of the second charging contactor, respectively; a first power connector having a first input terminal and a second input terminal electrically connected to the other end of the first charging contactor and the other end of the second charging contactor, respectively; and a control unit configured to, when a second power connector of a charger having a first output terminal and a second output terminal respectively, electrically connected to the first input terminal and the second input terminal, is connected to the first power connector and a charging end request signal is received, control the first charging contactor and the second charging contactor into a turn-off state, when the charging end request signal is received since the charging is completed or stopped in a state where the first power connector of the battery pack is connected to the second power connector of the charger, and diagnose a fault of each of the first charging contactor and the second charging contactor based on at least one of a first measured voltage, a second measured voltage and a third measured voltage respectively applied to the first measurement resistor, the second measurement resistor and the third measurement resistor.