A method of producing a non-aqueous electrolyte secondary battery includes at least the following (α), (β), and (δ): (α) preparing an elementary battery including at least a positive electrode, a negative electrode, a gel film, and an electrolyte solution; (β) carrying out initial charge of the elementary battery; and (δ) after the initial charge, processing the elementary battery to produce a finished-product battery. The negative electrode includes at least a negative electrode active material. The gel film is formed on a surface of the negative electrode. The gel film contains a polymer material and the electrolyte solution. The gel film is thixotropic. The initial charge is carried out while the gel film is under a first pressure. The processing is carried out in such a way that the gel film is put under a second pressure. The second pressure is higher than the first pressure.