The first smectic liquid crystal composition of the invention has a voltage gradation parameter L of less than 0.6, said parameter being defined by the equation L=S.sub.H /S.sub.O with the proviso that: a liquid crystal cell filled with a liquid crystal composition is placed between a pair of polarizing plates arranged in the crossed Nicols state; a voltage is applied to the liquid crystal cell to form a hysteresis curve showing a correlation between the voltage and a transmittance; and a tangent line I.sub.R of the hysteresis curve within a region wherein the transmittance steeply increases intersects a tangent line I.sub.F of the hysteresis curve within a region which is adjacent to the voltage-steep increase region and which is on the higher-voltage side at an intersection point P. In the above equation, S.sub.O is an area of a rectangular triangle having as an oblique side a straight line PQ which has, as both ends, the intersection point P and an intersection point Q of an axis of ordinate (V=0) and the hysteresis curve; and S.sub.H is an area of a region enclosed with the straight line PQ, the hysteresis curve and a constant-voltage straight line which passes the intersection point P. The second liquid crystal composition of the invention has a parameter G of 0 to 0.3, said parameter G being defined by the following equation with the proviso that when an absolute value .vertline.V.vertline. of a voltage V applied in the same manner as described above is increased to the predetermined value .vertline.V.vertline..sub.min, the light quantity T becomes a maximum value T.sub.max ; ##EQU1## In the above equation, S is an area of a region enclosed with the hysteresis curve, T.sub.min is a minimum value of the transmittance; and T.sub.0 is a transmittance given when no voltage is applied.