Disclosed herein is A battery pack comprising: a pack housing; a base plate; at least two battery modules arranged such that the battery modules are located in a space defined between the pack housing and the base plate, each battery module including a plurality of battery cells or unit modules which can be charged and discharged; a first wall located at a first side of the base plate; a second wall located at a second side of the base plate; an external input terminal and an external output terminal are located at both of the first wall and the second wall, the battery modules being connected to the external input and output terminals in a state in which the battery modules are electrically connected in series or in parallel to each other; and a capacitor is present at the first or second wall adjacent to a corresponding one of the external input and output terminals, the capacitor being electrically connected to said corresponding one of the external input and output terminals.