A method for manufacturing a lithium ion secondary battery includes steps of preparing a green sheet comprising at least one of lithium ion conductive inorganic powder and inorganic powder which becomes lithium ion conductive when it is heat treated; producing a thin film solid electrolyte by heat treating the green sheet; laminating an electrode green sheet comprising an active material on at least one surface of the thin film solid electrolyte; and heat treating the electrode green sheet at a temperature which is lower than a temperature at which the solid electrolyte is heat treated.