Abstract: Disclosed is a lithium ion secondary battery that has a simple structure, is easily produced, and wherein short circuits do not arise. The lithium ion secondary battery comprises an active material being contained in a matrix comprising a laminated body that includes a positive current collector and a negative current collector which are laminated on each other via a solid electrolyte layer, the solid electrolyte layer includes an active material in a matrix made of solid electrolyte, and a ratio of the volume of the solid electrolyte and the volume of the active material being 90:10-65:35. Also, the active material may also be contained in a matrix of a conductive substance of the positive current collector and/or the negative current collector.