A ferroelectric liquid crystal composition having a negative large dielectric anisotropy value, AC stabilizing effect at low voltages and yet high-speed response properties, and a light switching element using the composition are provided, which composition comprises at least two components at least one of which is a compound expressed by the formula ##STR1## wherein R.sup.3 and R.sup.4 each represent the same or different linear or branched alkyl group of 1-18C and l is 1 or 2, and having a negative dielectric anisotropy value.A preferred embodiment of the above composition contains at least three components A, B and C, one of which is the above compound of the formula (A) and components B and C of which are each selected from a group of specified compounds, and the respective proportions of components A, B and C being 5-50 weight %, 20-70 weight % and 5-40 weight % based on the total weight of the three, respectively.