To provide a method for purifying a liquid crystal compound, used for obtaining the liquid crystal compound which does not cause decrease in a voltage retention ratio even when exposed to a high temperature.

This method for purifying the liquid crystal compound comprises subjecting the liquid crystal compound which is composed of elements selected from the group consisting of carbon, hydrogen, fluorine, chlorine, and oxygen, and has no aliphatic unsaturated group to heat treatment in a specified temperature range and in an oxygen-containing atmosphere, so as to decompose the liquid crystal compound in a range of decomposition ratio of 0.5-10%, and then contacting the heat-treated compound to a silica gel on which a silver salt is supported, wherein the temperature range is specified so that the lower limit of the temperature range is lower than an extrapolated heat generation- initiating temperature (A; °C) by 20°C (A is a temperature corresponding to a peak existing on the lowest side among other peaks in a temperature region in which the liquid crystal compound exhibits an isotropic phase, when the peaks are obtained by a differential scanning calorimetric measurement on the liquid crystal compound in the oxygen-containing atmosphere) and the upper limit of the temperature range is higher than the temperature A by 150°C.