To provide a method for producing a polymerized rosin in a simple production step and with efficiency without using highly advanced facilities, and furthermore a novel method for efficiently/economically producing a polymerized rosin by using the recovered catalyst.

The method for producing a polymerized rosin comprises polymerizing a rosin in the presence of a copolymer composed of (a) an ethylenically unsaturated monomer and (b) a crosslinkable monomer copolymerizable with the monomer (a) and having an average particle diameter of 0.1-3 mm, a specific surface area of 1-70 m2/g, a pore volume of 0.1-1 ml/g, an average pore diameter of 100-1,500 , and a content of an acid functional group of 2.0-7.0 milliequivalents/g. Further, the method for producing a polymerized rosin comprises polymerizing a rosin with the reuse of the recovered copolymer.