<p>Disclosed is a method for synthesizing t-butyl (meth)acrylate at low cost. Specifically, disclosed is a method for synthesizing a carboxylic acid ester by performing an addition reaction between isobutylene and (meth)acrylic acid in the presence of an acidic catalyst. This method includes the steps of:
(A) performing a dehydration decomposition reaction of t-butyl alcohol in the presence of a first acidic catalyst;
(B) obtaining crude isobutylene gas by separating at least water from a produced gas obtained in the step A;
(C) absorbing the crude isobutylene gas in an absorption solvent containing (meth)acrylic acid; and
(D) producing t-butyl (meth)acrylate by performing the addition reaction by bringing the absorption solvent which has absorbed the crude isobutylene gas into contact with a second acidic catalyst.</p>
