The present invention provides a method for producing a lithium-ion secondary battery with excellent high-temperature storage characteristics. The method for producing the lithium-ion secondary battery provided by the present invention includes a step of assembling a lithium-ion secondary battery using positive and negative electrodes, and a nonaqueous electrolyte containing in an organic solvent a lithium salt as a supporting salt, at least one type of substance selected from carboxylic acid anhydrides and dicarboxylic acids as additive A, and at least one type of substance selected from vinylene carbonate, vinylethylene carbonate, ethylene sulfite, and fluoroethylene carbonate as additive B; a step of carrying out initial charging of the assembled battery to a predetermined voltage; and a step of carrying out an aging treatment by keeping the battery at a temperature of 35° C. or higher for 6 hours or longer.