A method is disclosed for industrially producing a Japanese encephalitis vaccine, wherein (a) cells from a cell line are cultured, (b) the resulting cell culture is inoculated with a Japanese encephalitis virus in the presence of a viral growth medium, (c) the virus is propagated and multiplied on the cells, (d) the viral growth medium is recovered in the form of a suspension of viruses produced by the cells, (e) the virus suspension is purified in at least one ion exchange chromatography step and a gel permeation step, and (f) the virus suspension is formulated and converted into a pharmaceutical form to preserve it until the moment of use. A Japanese encephalitis vaccine characterised in that it comprises a Japanese encephalitis virus produced by culturing cells from a cell line, and in that the cellular DNA content is less than 100 pg/dose, is also disclosed.