A battery pack includes a battery cell, an input/output terminal to/from which a charging/discharging current of the battery cell is to be inputted/outputted, and a connector detachably connected to the input/output terminal, and the input/output terminal includes a first hollow conductive member protruding in a first direction and a second hollow conductive member protruding to surround an outer periphery of the first hollow conductive member, the connector includes a central guide protruding in a second direction opposite to the first direction and a third hollow conductive member protruding to surround the outer periphery of the central guide, the central guide is fitted into a hollow portion of the first hollow conductive member, and the third hollow conductive member is fitted into a space between the first and second hollow conductive members and is electrically connected to the first and second hollow conductive members by an elastic connection member.