A battery manufacturing apparatus is configured to produce a plurality of types of battery modules (first battery module and second battery module) having a cell unit (flat battery) housed inside a case having an upper case and a lower case and having different specifications between a plurality of components (bolted brackets and sleeves) attached to the case. The battery manufacturing apparatus has a first attachment mechanism, a second attachment mechanism and a battery housing mechanism. The first attachment mechanism attaches to one of the upper case and the lower case of the plurality of components having different specifications. The second attachment mechanism attaches to one of the upper case and the lower case of the plurality of components having no specification differences. The battery housing mechanism has a flat battery arranged between the upper case and the lower case.