Abstract: A battery pack includes a spacer. The spacer for the battery pack can be used by being cut according to the number of batteries received in the battery pack, and can thus be applied to multiple battery packs in which different numbers of batteries are received, and can be easily separated manually. In one type of spacer, a first plurality of concave battery receiving parts corresponding to portions of outer surfaces of the cylindrical batteries are formed on a first surface of a rectangular frame, and cutting grooves are formed in the respective battery receiving parts in a direction corresponding to the center axes of the cylindrical batteries to facilitate cutting of the spacer.