A battery pack includes: a battery stack; a housing that houses the battery stack; and a skeleton part that is housed in the housing and reinforces the housing. The skeleton part includes a stem extending in a first direction, a plurality of branch portions that protrude from the stem and are arranged in a row in the first direction, and a plurality of housing spaces, each of the housing spaces being defined by a pair of branch portions disposed adjacently to each other and housing the battery stack. The stem and the plurality of branch portions are fixed to the housing.