Disclosed herein is a bus bar connected or fastened to a terminal part of a battery pack and fixedly mounted to a battery pack case, the bus bar including a power input part located at one end of the bus bar such that the power input part is connected or fastened to an output terminal part of the battery pack, a power output part located at the other end of the bus bar such that the power output part is connected or fastened to an input terminal part of the battery pack, a plate-shaped main body connected between the power input part and the power output part, the plate-shaped main body including a vapor chamber, and a fastening part formed at the power input part to fix the bus bar to the battery pack case.