One aspect of the invention provides a liquid crystal display device producing method for irradiating a liquid crystal display substrate, in which plural pixels are formed in a matrix state and liquid crystal is sealed between a TFT substrate and a counter electrode substrate, with light having a predetermined wavelength to orient liquid crystal molecules toward a predetermined direction in a state in which an electric field is applied to each pixel of the liquid crystal display substrate. The method includes the steps of: dipping the liquid crystal display substrate and a lamp in a transparent liquid having resistivity of a predetermined value or more and sufficiently high transmittance to the light in a state in which the liquid crystal display substrate and the lamp face each other; and lighting the lamp to irradiate the liquid crystal display substrate with the light having a predetermined light quantity in a state in which the electric field is applied to each pixel.