A battery pack includes: a plurality of battery cells in a plurality of rows in a row direction, the battery cells being arranged such that rows adjacent to each other in a transverse direction crossing the row direction are alternately shifted to forward and backward positions in the row direction; a busbar extending in the row direction, the busbar including: a busbar body portion extending in the row direction; a busbar front connection portion at one end thereof; and a busbar rear connection portion at another end thereof, the busbar front connection portion and the busbar rear connection portion protruding from the busbar body portion and having different lengths and levels from each other; and a case accommodating the battery cells, the case including a front wall and a rear wall having complementary shapes and facing each other in the row direction with the battery cells therebetween.