A lithium ion secondary battery. The battery maintains an electrical connection between electrodes without using a firm case and can have an increased energy density at a reduced thickness while exhibiting excellent charge and discharge characteristics. The battery includes a plurality of electrode laminates each having a positive electrode, a negative electrode and a separator. The positive electrode includes a positive electrode active material layer and a positive electrode current collector. The negative electrode includes a negative electrode active material layer and a negative electrode current collector. This separator is impregnated with a lithium ion-containing electrolytic solution and is interposed between the electrodes in intimate contact. The positive electrode, negative electrode and separator are joined together in intimate contact with porous adhesive resin layers having through holes. The through holes are filled with electrolytic solution to connect the positive electrode active material layer, the negative electrode active material layer and the separator layer.