The present invention provides an electricity storage module which has low contact resistance between an electricity storage cell and a bus bar, while having excellent connection strength; a method for manufacturing an electricity storage module; a metal bonded body; and a method for producing a metal bonded body. An electricity storage module according to the present invention is provided with anelectricity storage cell and a frame. The electricity storage cell is provided with: an electricity storage element having a positive electrode and a negative electrode; an outer package film that seals the electricity storage element together with an electrolyte; a positive electrode tab that is formed of a first metal material and is electrically connected to the positive electrode; and a negative electrode tab that is formed of a second metal material and is electrically connected to the negative electrode. The frame forms a container space for containing the electricity storage cell and is provided with a bus bar that is formed of the second metal material. The positive electrode tab and the bus bar are bonded with each other by welding; and a material mixed part wherein the first metal material and the second metal material are mixed is formed at the interface between the positive electrode tab and the bus bar.