PURPOSE: To obtain the titled copolymer useful as an anion exchange resin, etc. having improved heat resistance and chemical resistance, containing imidazole and imidazoline, by reacting a copolymer of a divinyl benzene, styrene, cyanostyrene, etc. with an ethylenediamine.

CONSTITUTION: A divinyl benzene is copolymerized with a styrene and a cyanostyrene to give a crosslinked terpolymer having (A) 2W50mol% polymerization unit shown by the formula I (R1 is H, or 1W4C hydrocarbon), (B) 0W50mol% polymerization unit shown by the formula II (R2 is as shown for R1), and (C) 10W98mol% polymerization unit shown by the formula III (R3 is as shown for R1), it is reacted with an ethylenediamine to give the desired copolymer having 0W30mol% unit of the component C, (D) 10W98mol% polymerization unit shown by the formula IV and (E) 0W30mol% polymerization unit shown by the formula V.