An electrode structure for connecting a battery module to a bus bar is provided. When a bolt is in advance passed through and temporarily fixed to a metal terminal to be connected to a bus bar, the metal terminal is fixed on a lid, and the lid is attached to a body of a battery module, there was a problem that metal powder generated by the friction between the metal terminal and the bolt intrudes into the battery. A solution to the problem is provided by an electrode structure including a metal terminal having a base and a tip end, the base fixed to a body of a battery module, the tip end spaced apart by a predetermined distance from the body of the battery module and connected to a bus bar, a nut arranged between the tip end of the metal terminal and the body of the battery module, a rotation stopper in abutment with the nut and preventing the nut from slipping when fastening the bus bar, and a screw shaft screwed into the nut and penetrating through the tip end of the metal terminal and the bus bar.