An electrode is provided with a metal terminal extending from a battery module main body, a bolt which has an expanded section configuring a retaining section at a rear end portion and penetrates the metal terminal upward, and an insulating body which insulates the metal terminal and the battery module case one from the other. The insulating body is provided with a drop preventing section which abuts at least a lower surface of the expanded section of the bolt and prevents the bolt from dropping from the metal terminal.