An object of the present invention is to provide a non-aqueous electrolyte secondary cell that provides good wettability between the non-aqueous electrolyte and the separator and that is superior in cycle characteristics. This object is solved by a method for producing a non-aqueous electrolyte secondary cell, the cell having: an electrode assembly having a positive electrode, a negative electrode, and a separator located between the electrodes; and a non-aqueous electrolyte having an electrolytic salt and a non-aqueous solvent having a solvent with a dielectric constant of equal to or more than 30 at 25° C., the solvent being equal to or more than 50 volume %, the method having: adding in the non-aqueous electrolyte an isocyanate compound and a compound represented by R—(CH2—CH2—O—)nH where R is an alkyl derivative or a phenyl derivative, and n is an integer of equal to or more than 2; and allowing the two compounds to have an urethane bonding reaction therebetween.