There is provided a battery module 100 including batteries 1 and 2 and a connection body 3 between the batteries 1 and 2 which electrically connects in series a metal electrode 1b of negative electrode of the battery 1 and a metal electrode 2a of positive electrode of the battery 2, wherein the connection body 3 includes a first connection portion 3b which is electrically connected to the metal electrode 1b of the battery 1 and a second connection portion 3 a which is electrically connected to the metal electrode 2a of the battery 2 and is arranged in a region which overlaps with the individual batteries 1 and 2 when the individual batteries 1 and 2 connected by the connection body 3 are viewed in a plan view from one of two sides in a direction S of series connection of the individual batteries 1 and 2.
