PURPOSE: To obtain the title copolymer which exhibits high-speed response to a change of an electrical field, shows the SmC* phase at room temperature, and is excellent in bistability by selecting a liquid crystal copolymer having a plurality of specific repeating units in a prescribed ratio.

CONSTITUTION: A liquid crystal copolymer which has repeating units of formulae I and II (wherein R1 is a group of formula III; R2 is a group of formula IV; R3 and R6 are each a group of formula V-XI; R4-5 and R7-8 are each CH3, CF3, CN or halogen; X1-2 and Y1-2 are each -COO-, -OCO-, -O- or a single bond; Z1-2 are each -COO-, -OCO- or -O-; a and d are each 1-30; c and i are each 0-10; e is 0-5; b, f, g, h and j are each 0 or 1; and when h=j=1 and Z1=Z2, R3≠R6) in a molar ratio of 99:1 to 1:99.