PURPOSE: To produce the titled high-molecular compound in good yields, by reacting a specified high-molecular compound with an epihalohydrin in the presence of a phase transfer catalyst and dehydrohalogenating the product.

CONSTITUTION: A halohydrin ester of formula IV (wherein X is a halogen) is obtained by reacting an epihalohydrin with a high-molecular compound, MW of 1,000W1,000,000, of formula III (wherein the ratio of x to the sum of x and y is 0.99), obtained by radical- or anion-copolymerizing monomers of formulas I and II(wherein R1W7 are each H, a 1W10C hydrocarbyl group, -COOMe, -COOEt, a halogen, or cyano) at 40W120°C for 5minW2hr in the presence of a phase transfer catalyst (e.g., tetrabutylammonium bromide). After adding a dehydrohalogenating agent (e.g., NaOH), the halohydrin ester is dehydrogenated at 0W70°C for 10minW2hr to obtain a glycidyl ester group-containing high-molecular compound of formula V.