The battery module has a structure in which a plurality of batteries are arranged at fixed positions by a battery holder, a lead plate is connected to a projecting electrode of each of the batteries, a potting resin is thermally coupled to the lead plate, the battery holder includes an outer peripheral cover having an electrode window to expose the projecting electrode, the lead plate has a connection recess that is locally formed in a planar part to let a protrusion face protrude toward the projecting electrode through the electrode window, and a sealing label is put into intimate contact with the planar part of the lead plate to close an opening of the connection recess. This structure prevents the potting resin from flowing into an outlet formed in the projecting electrode.