The present invention discloses a battery module capable of improving efficiency in installation of a plurality of battery module by connecting and expanding thereof. The battery module, achieving the purpose of the present invention, comprises: a plurality of cylindrical battery cells; a module housing having an accommodating part; a bus bar electronically connected to electrode terminals of at least two cylindrical battery cell; and a current collecting plate contacting with another current collecting plate , thereby electronically connected to a plurality of cylindrical battery cells of another battery module, wherein a guide coupling structure, including a coupling protrusion and a guiding groove, is formed to guide an arrangement location of another battery module on an outer surface of an external wall of the module housing.